Ashwaganda seems to be a relatively safe traditional Ayurvedic herbal medicine. A few thing to consider before trying it:
Talk to your treating physicians, especially if you meet any of the cautionary criteria below, or before being prescribed any new medications.
Ashwaganda is an unregulated supplement. Make sure you buy if from a reliable source, some tests have indicated it may be contaminated with an unsafe level of lead when bought indiscriminantly.
Like many other supplements, it can be unsafe for certain people.
If you have prostate cancer or are/may be pregnant it should not be taken.
If you have diabetes, it should only be taken with the knowledge of your doctor. It can affect blood sugar and how diabetes medications work.
It may interact with the medications in the following classes: sedatives and medications with sedating effects, blood pressure medications, immunosuppressants and diabetes medication.

Please ley us know if it works (or not) for you.
Sue