In Brief: Is it Safe to Take Ashwagandha Daily?
Ashwagandha appears to be safe and well-tolerated when taken for a short term. Milder side effects, including diarrhea, and vomiting, may occur. Liver injury may occur in rare instances. Future research studies are required to examine the efficacy and safety of long term effects of ashwagandha.
Studies showed that high concentrations of ashwagandha root extract are generally safe and well-tolerated with no serious adverse effects.
Large doses, however, can cause gastrointestinal upset, diarrhea, nausea, and vomiting due to direct irritation to the intestinal mucosa.
A single-center, placebo-controlled randomized trial showed that 300mg of high concentration, the full-spectrum extract of ashwagandha, showed a significant reduction in stress scores.
The side effects reported, including constipation, drowsiness, decreased appetite, were mild and comparable to the control.
Another randomized placebo-controlled study showed that 300mg of full-spectrum Ashwagandha root extract given to patients with insomnia and anxiety for ten weeks was well-tolerated. None of the patients reported any adverse effects.
The ethanolic extract of ashwagandha was well tolerated. It did not show any more adverse effects than a placebo in a study involving its treatment for anxiety disorders.
A randomized controlled trial showed that 300mg of ashwagandha taken twice per day for 60 days showed a reduction in stress without any adverse effects.
Eighteen volunteers received ashwagandha capsules daily in two divided doses with an increase in daily dosage every ten days for 30 days.
Only one volunteer had an increased appetite, libido, and hallucinogenic effects, and the rest did not report any side effects.
An investigation demonstrated that the extract of ashwagandha did not result in any treatment-related gross, pathological lesions, or adverse effects in Wistar rats.
Some case studies reported adverse effects of taking ashwagandha.
Recently, several cases of clinically apparent liver injury have been reported in patients taking herbal products containing ashwagandha.
It is not very clear if the reported cases were because of ingesting ashwagandha or any other contaminant. The liver injury subsided within 1 to 3 months of not taking the herbal product. 
A participant in one study had increased appetite, libido, and vertigo with a low dose of ashwagandha. Hence, the participant had to be dropped from the study. 
A 28- year old man with decreased libido experienced burning, itching sensation, and discoloration of the skin after taking 5g of ashwagandha for ten days.
A study showed that withaferin extracted from ashwagandha did not show any grade 3 or grade 4 adverse events. There was an elevation of liver enzymes, skin rash, fatigue, fever, edema, and diarrhea.
It is advised to stop taking ashwagandha during pregnancy and breastfeeding as there are not enough research studies supporting its safety.
An animal study showed that ashwagandha extract (2000mg/kg/day) caused no changes in the bodyweight of parental females, viable fetuses, and visceral malformations.
Also, as it can boost immune response, people with autoimmune disease should avoid ashwagandha.
Although these short term studies indicate that ashwagandha supplementation is generally safe and well-tolerated with minimal side effects.
However, long-term safety and effective dose of ashwagandha supplementation are unknown.
Therefore, more large randomized controlled studies with a larger population are required to determine the safety and efficacy of ashwagandha for the long term.