Ashwagandha is an ancient medicinal herb with multiple health benefits. It can reduce anxiety and stress, help fight depression, boost fertility and testosterone in men, and even boost brain function.Ashwagandha is safe when taken by mouth for few days . Large doses of ashwagandha might cause stomach upset, diarrhea and vomiting. It’s dosage depends on factors including your age, gender, and medical history. Speak to your healthcare provider for advice.