Part 3 of 6 in the "Chinese herbs and Western medication" series. All six are listed at the foot.

This is a question many people search for, and the answer has two layers: a number, and the limit of that number.

The short version

• As a general rule, Chinese and Western medicines are taken at least one to two hours apart — that is what Hong Kong's Hospital Authority writes, and China Medical University's Institute of Integrated Chinese and Western Medicine says the same.
• In the same paragraph the Authority continues: this only avoids interactions caused by direct contact in the stomach, and cannot avoid potential interactions once the medicines have been absorbed.
• Spacing solves "swallowed together", not "in the body together". It reaches station ① absorption from part 2; ② to ⑥ — distribution, metabolism, excretion, additive, antagonistic — it does not reach.
• Two more routes lie outside its reach: ⑤ additive (both sides pushing the same way) and ⑥ antagonistic (pushing opposite ways). These two are the pharmacodynamic half from part 1.
• The Authority's own two teaching examples are exactly these: 麻黄汤 with added paracetamol, and far too much sweating; and liquorice taken long-term in larger doses, weakening the effect of blood-pressure medication.
• The simplest arrangement: leave your Western medication where it is and place the herbs at least one to two hours away. If your practitioner gives a different gap, follow the written instruction.

First, the one thing never to do

⚠️ A safety note: TCM and Western medicine complement each other. It is not a choice between them. This part names Western drug classes. Whichever one you recognise, never stop on your own — do not stop, reduce or adjust any prescribed Western medication because you read this, since changes to a prescription are decided by the doctor who wrote it.

The full account is in part 1.

A note: this section is general information only. For conditions like these, follow your doctor's diagnosis and treatment, and seek medical attention when you need it.

I. How far apart: usually at least one to two hours

First layer, the number. As a general rule, Chinese and Western medicines are taken at least one to two hours apart — that is what the Hospital Authority writes. China Medical University's Institute of Integrated Chinese and Western Medicine says the same: a one-to-two-hour gap may reduce some of the absorption interference caused by both being in the gut at once.

Second layer, the limit of the number. In the same paragraph the Hospital Authority continues: this only avoids interactions caused by direct contact in the stomach, and cannot avoid potential interactions once the medicines have been absorbed. Spacing solves "swallowed together", not "in the body together".

The Hospital Authority's Smart Patient lecture material says the same: the gap of at least one to two hours is there to avoid interactions caused by direct contact in the gut. Set against part 2: spacing addresses station ① absorption; ② to ⑥ happen after the medicine is in the body, where spacing does not reach.

• The simplest arrangement: keep your Western medication at its usual time and place the herbs at least one to two hours away from it. For example, Western medication with breakfast, herbs two hours after that.
• If both are taken several times a day, write the day's timetable down and show it at the consultation.
• If your practitioner gives a different gap for a specific prescription, follow the written instruction. It fits your situation more closely than the general rule.

II. The two routes a gap does not reach: ⑤ additive, ⑥ antagonistic

Part 2's four stations are about how the body handles a medicine. The two remaining routes run the other way: what two medicines do to the body, either stacked together or cancelling each other out. This is the pharmacodynamic half from part 1.

⑤ Additive: both sides push the same way. The Hospital Authority's teaching example: a patient has fever, chills, a runny nose, aching head and body, and a wheezing cough without sweating; the TCM diagnosis is wind-cold common cold, the treatment principle is to induce sweating and release the exterior, and the prescription is 麻黄汤 (Ephedra Decoction).

The patient adds paracetamol on their own, sweats far too much and develops 虚脱 (collapse). Two sweat-inducing actions stacked, and it went too far. That is "additive".

Notice which step went wrong in that example: not the prescription, but adding something on your own. Neither side knew what the other was doing.

⑥ Antagonistic: the two sides push opposite ways. Constituents of 甘草 (liquorice) have a steroid-hormone-like action; taken long-term in larger doses, liquorice can reduce urine output, so water is retained in the body, blood pressure rises, and the effect of blood-pressure medication is weakened. That account is the Hospital Authority's too.

The Hospital Authority labels liquorice "tonifies the spleen and qi, harmonises the other herbs". It is common in prescriptions; dose and duration are the practitioner's to manage, which presumes the practitioner knows you take blood-pressure medication.

Both of these routes happen after the medicine is already inside the body. Which is precisely where "two hours apart" does not reach.

A note: this section is general information only. For conditions like these, follow your doctor's diagnosis and treatment, and seek medical attention when you need it.

III. These are examples, not a list

These are the Hospital Authority's examples, not a list where anything unlisted is safe. One herb can appear under several routes (黄连, 甘草 and 山楂 all do), which is why the judgement is made on your whole medication list.

Do not stop or reduce any Western medication named in this part because you read this; take the list and the question to the prescribing doctor.

The words in this part

• Pharmacodynamics (药效学) — the Hospital Authority's gloss: what a medicine does to the body. Both ⑤ additive and ⑥ antagonistic sit here; the full account is in part 1.
• Additive (作用叠加) — the Authority's name for the fifth route: two medicines' effects on the body push the same way and add up. Its example is 麻黄汤 with paracetamol, both of which induce sweating.
• Antagonistic (作用抵消) — the name for the sixth route: the two effects push opposite ways and weaken each other. Its example is liquorice long-term in larger doses, against blood-pressure medication.
• Inducing sweating and releasing the exterior (发汗解表) — the treatment principle the Authority records in that teaching example, which is what the prescription it records was meant to do. It is written about that one case, and is not for a reader to apply to themselves.
• 虚脱 (collapse) — the Authority's word for how that example ended: far too much sweating, then 虚脱.

Frequently asked

Can I take Chinese and Western medicine at the same meal? Generally not advised. At least one to two hours apart is the usual practice, as Hong Kong's Hospital Authority writes it; if your practitioner gives a different instruction, follow it. The Hospital Authority also cautions: even with these measures, Chinese and Western medicines may still interact inside the body; in most cases the effect is mild, but you still need to watch how you feel closely and consult a healthcare professional when needed.

So would four hours, or six, be safer still? That does not follow. What the Hospital Authority gives is "at least one to two hours", and what it explains is what that gap avoids and what it does not — it does not say that stretching it reaches ② to ⑥. A longer gap is not free, either: do not rewrite your Western medication schedule yourself. If it needs adjusting, ask the prescribing doctor and your TCM practitioner.

The other five parts

• Part 1: Can you take Chinese herbs with Western medication? The answer first, and the one thing never to do
• Part 2: How it actually happens: the four stations a medicine passes in the body
• Part 4: Which Western drug classes need extra care: the two with a narrow window, plus blood-pressure and blood-glucose medication
• Part 5: Red yeast rice and statins: when the supplement contains the drug, and three more classes to mention
• Part 6: What actually happens at the consultation, and fitting it into life in Malaysia

👉 If you are on Western medication and want to know how Chinese herbs should be arranged around it, you are welcome to book an online consultation with HansMed, where a practitioner registered under the T&CM Act 2016 assesses it with your medication list in view. Make sure your doctor knows about the arrangement too; safety rests on both sides having the full picture.

Sit with a licensed TCM practitioner from wherever you are.

HansMed Modern TCM

Sources

• Hospital Authority, Hong Kong, HASLink July 2024, "中西藥相互作用知多少" — https://www3.ha.org.hk/ehaslink/issue132/tc/feature-3.html
• Hospital Authority, Hong Kong, Smart Patient lecture deck, 《當中藥師遇見藥劑師——認識中西藥相互作用》, PDF created 9 July 2024 — https://www.smartpatient.ha.org.hk/smart-patient-web/useful-information/sp-series/sp-series-details/%E8%97%A5-%E5%AF%86-%E8%A7%A3%E9%8E%96%E8%AC%9B%E5%BA%A7
• Institute of Integrated Chinese and Western Medicine, China Medical University, "中藥、西藥宜間隔多少時間？", page text updated 22 July 2026 — https://dhi.cmu.edu.tw/info/index.php?option=com_content&view=article&id=63&Itemid=83

本文是「中药和西药」系列的第 3 篇，共 6 篇。六篇的清单在文末。

这是很多人会搜的问题，答案有两层：一个数字，和这个数字的限度。

一分钟看完

• 一般而言，中药和西药相隔至少一至两小时服用——香港医院管理局这样写；中国医药大学中西医结合研究所的说法相同。
• 医院管理局在同一段话里接着说：这只能避免药物在胃部因直接接触产生的相互作用，无法避免药物吸收进入人体后的潜在相互作用。
• 换句话说，间隔解决的是「同时吞下」，不是「同时在身体里」。它管得到第 2 篇的①吸收那一站；②到⑥（分布、代谢、排泄、叠加、抵消）管不到。
• 间隔管不到的还有两种方式：⑤ 作用叠加（两边往同一个方向推）与⑥ 作用抵消（往相反方向推）。这两种是第 1 篇说的药效学那一半。
• 医院管理局的两个教学例子就说明这两种：麻黄汤加 paracetamol 导致汗出太多，以及久服较大剂量的甘草减弱降血压药的效果。
• 最简单的排法：西药时间不动，中药排在与它相隔至少一至两小时的时段。医师给了不同的间隔，以医师的书面指示为准。

先说绝对不要做的一件事

⚠️ 安全提醒：中医与西医是互相补位的关系，不是二选一。这一篇点名了西药类别。看到哪一类，都切勿自行停药——不要因为读到这里就自行停用、减量或调整任何西医处方药，处方药的调整只能由开立那个处方的医师决定。

完整说明见第 1 篇。

小提醒：本段仅为一般知识说明。相关情况请以西医的诊断与治疗为主，并在需要时及时就医。

一、隔多久：一般至少一至两小时

第一层，数字。 一般而言，中药和西药相隔至少一至两小时服用——香港医院管理局这样写。中国医药大学中西医结合研究所的说法相同：相隔一至两小时可能减少两者同时在肠胃道造成的部分吸收干扰。

第二层，数字的限度。 医院管理局在同一段话里接着说：这只能避免药物在胃部因直接接触产生的相互作用，无法避免药物吸收进入人体后的潜在相互作用。换句话说，间隔解决的是「同时吞下」，不是「同时在身体里」。

医院管理局的「智友站」讲座材料说法一致：相隔至少一至两小时，是为了避免药物在胃肠道因直接接触产生的相互作用。对照第 2 篇：间隔管的是①吸收这一站；②到⑥发生在药进入身体之后，间隔管不到。

• 最简单的排法：西药固定在原来的时间不动，中药排在与它相隔至少一至两小时的时段。例如西药随早餐服用，中药则在两小时后再服。
• 两边都要服用多次的，把一天的时间表写下来，看诊时给医师看。
• 医师针对某个处方给了不同的间隔，以医师的书面指示为准，它比通则更贴近您的情况。

二、间隔管不到的那两种：⑤ 叠加、⑥ 抵消

第 2 篇的四站讲的是人体怎么处理药。剩下的两种方式讲的是另一个方向：两种药对身体的作用，是叠在一起，还是互相抹掉。这就是第 1 篇说的药效学那一半。

⑤ 作用叠加：两边往同一个方向推。 医院管理局的教学例子：病人发烧、怕冷、流鼻水、头身痛、无汗而喘咳，中医诊断为风寒感冒，治法是发汗解表，处方麻黄汤。

病人自行加服 paracetamol（扑热息痛），结果汗出太多，出现虚脱。发汗的作用叠在一起，就过了头。这就是「叠加」。

请注意这个例子里出问题的那一步：不是处方，是自行加服。两边的医师都不知道另一边在做什么。

⑥ 作用抵消：两边往相反方向推。 甘草中的成分有类固醇激素作用，久服较大剂量的甘草可使尿量减少，水分在体内滞留，引起血压升高，从而减弱降血压药的效果。这也是医院管理局的说明。

医院管理局标注甘草「补脾益气，调和诸药」——它在处方里很常见，剂量与服用时长由医师掌握，前提是医师知道您在吃降血压药。

这两种方式都发生在药已经进入身体以后。所以它们正是「隔两小时」管不到的地方。

小提醒：本段仅为一般知识说明。相关情况请以西医的诊断与治疗为主，并在需要时及时就医。

三、这些是例子，不是清单

这些是医院管理局举的例子，不是「没列到就安全」的清单。同一味药材可以出现在好几种方式里（黄连、甘草、山楂都是），所以判断要看您的整份药单。

本篇提到的任何西药，都不要因为读到这里而自行停用或减量；有疑问，带着药单问开药的医生。

这篇出现的几个词

• 药效学（pharmacodynamics）——香港医院管理局的说法：药物对人体的作用。⑤ 叠加与 ⑥ 抵消都属于这一类；完整说明在第 1 篇。
• 作用叠加——医院管理局给第五种方式的名字：两种药对身体的作用往同一个方向推，加在一起。它的例子是麻黄汤与 paracetamol，两样都发汗。
• 作用抵消——第六种方式的名字：两种药的作用往相反方向推，互相减弱。它的例子是久服较大剂量的甘草与降血压药。
• 发汗解表——医院管理局在那个教学例子里记下的治法，也就是它所记的那张处方要做的事。这是写在那一个病例上的，不是给读者对号入座的。
• 虚脱——医院管理局用来描述那个例子结果的词：汗出太多之后出现虚脱。

常见问题

中药和西药可以同一餐吃吗？ 一般不建议。至少相隔一至两小时是通行做法，这是香港医院管理局写的；医师若给了不同指示，以医师为准。医院管理局也提醒：即使采取了这些措施，中西药仍可能在体内产生相互作用，虽然大多数情况下影响较轻微，但仍需密切留意身体状况，并在需要时咨询医疗专业人员。

那我把间隔拉到四小时、六小时，是不是更安全？ 不能这样推。医院管理局给的是「至少一至两小时」，它说明的是这个间隔能避免什么、不能避免什么——没有说拉长就能避免②到⑥。更长的间隔也不是没有代价：西药的服药时间表不要自己改。要调整，请问开药的医生与您的中医师。

这个系列的另外五篇

• 第 1 篇：中药和西药可以一起吃吗？先给答案，和绝对不要做的那一件事
• 第 2 篇：它是怎么发生的：一颗药在身体里经过的四站
• 第 4 篇：哪几类西药要特别小心：治疗窗窄的两种，加上降血压药与降血糖药
• 第 5 篇：红曲与他汀：保健品里就有同一种成分，以及另外三类要说清楚的药
• 第 6 篇：看诊时实际会发生什么，以及大马生活里怎么安排

👉 如果您正在吃西药，想知道中药该怎么安排，欢迎透过汉方中医的线上问诊，由依 2016 年 T&CM 法令注册的医师看着您的药单为您评估。请同时让您的医生知道这个安排，两边都掌握资讯，才是安全的前提。

无论身在何处，与持证中医师对坐。

汉方现代中医

资料来源

• 香港医院管理局，《协力》2024 年 7 月号〈中西药相互作用知多少〉— https://www3.ha.org.hk/ehaslink/issue132/tc/feature-3.html
• 香港医院管理局「智友站」讲座简报，《當中藥師遇見藥劑師——認識中西藥相互作用》，PDF 建档 2024 年 7 月 9 日 — https://www.smartpatient.ha.org.hk/smart-patient-web/useful-information/sp-series/sp-series-details/%E8%97%A5-%E5%AF%86-%E8%A7%A3%E9%8E%96%E8%AC%9B%E5%BA%A7
• 中国医药大学中西医结合研究所，〈中药、西药宜间隔多少时间？〉，页面文字 2026 年 7 月 22 日更新 — https://dhi.cmu.edu.tw/info/index.php?option=com_content&view=article&id=63&Itemid=83