What vitamins and herbs should not be taken together?
Michael King
Updated on April 07, 2026
What vitamins and herbs should not be taken together?
Let’s take a look at five supplement combos you should avoid.
- Multivitamins. But, before we get to that, we need to address the elephant in the room: multivitamins.
- Calcium and magnesium.
- Copper and zinc.
- Fish oil and Ginkgo biloba.
- Iron and green tea.
- Melatonin and St.
- Plan A.
What is the herbal drug interaction?
Any pharmacological modification caused by herbal substances to another prescription medication (diagnostic, therapeutic or other action of a drug) in or on the body. An herb might increases or decreases the effects of co-administered drugs.
Can herbs interfere with prescription drugs?
Herbal supplements can have strong effects in the body. Some can interact with prescription medications used to treat heart and circulatory problems, such as high blood pressure and heart failure. Some of these interactions can even be dangerous.
Which of the following drug is commonly having more herb drug interaction?
Although St. John’s wort interacts with most drugs pharmacokinetically, pharmacodynamic interaction of St. John’s wort with several drugs has also been reported….25.7 Drug–Herb Interactions Involving St. John’s Wort and Warfarin–Herb Interactions.
| Drug Class | Comments |
|---|---|
| Anti-asthmatic agents | Reduced levels of theophylline. |
Can herbs interact with each other?
Even though herbal supplements may be from plant or herb sources, the active ingredients can still be potent chemicals. Because of this, herbal supplements can have drug interactions, even with each other or with food or alcohol.
What herbs interact with mental health drugs?
References
| Herb | Promoted use | Safety |
|---|---|---|
| Ginkgo biloba | Dementia, memory | Bleeding complications, drug interactions a concern |
| St. John’s wort | Depression | Substantial drug interactions |
| Kava kava | Anxiety | Hepatotoxicity risk, drug interactions; off market in Europe and Canada |
| Valerian | Insomnia | Limited data available |
How long do herbs stay in your system?
They stay in the system for three to four hours at most, so they require a longer-term regimen. Each formulation has anywhere from two to 50 individual herbs, and the formulations are made for the individual, depending on what’s going on with them.
What are the most common drug interactions?
Which are Some Common Drug-Drug interactions?
- Digoxin and Amiodarone.
- Digoxin and Verapamil.
- Theophylline and Quinolones.
- Warfarin and Macrolides.
- Warfarin and Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
- Warfarin and Phenytoin.
- Warfarin and Quinolones.
- Warfarin and Sulfa Drugs.
Do herbs interact with other herbs?
