There are some precautions when taking Ashwaghanda.
1. If you are taking meds for thyroid, Ashwaghanda can increase the effects of those meds. Check with a doctor, and monitor.
2. If you are alergic to the nightshades (pototoes, tomatos, eggplant, etc.), Aswhaghanda may also cause a reaction, such as nausea, diarrhea, headaches -- not in everyone, but in some cases.
3. Ashwaghanda can lower blood sugar levels, so if you are on meds for diabetes, consult with a doctor first (in my search, ashwaghanda is NOT recommended in such cases).
4. In some rare cases, ashwaghanda caused skin discoloration, burning and/or itching of the penis, lips and hands (I'm not making this up) -- rare, but if it happens, the syptoms are resolved when the ashwaghanda was stopped. This happened when taking large doses of 5 grams a day (which most people don't do).
5. If you are an organ transplant recipient, ashwaghanda may interfere with immunosuppressant meds because ashwaghanda stimulates the immune system.
6. Ashwaghanda has some blood-thinning effects. If regularly using drugs such as aspirin (including advil, ibuprofin, etc), or coumadin, etc., exercise caution.
I got this info from consumerlab.com. I'm not recommending against Ashwaghana -- for most people, it works great. Just sharing for everyone's info.