sir, in siddha aswagandha is rejunevating medicine. it helps to improve your immunity, calms your nerve tissues and repairs damages to nerve tissues. you can take regularly for longer period and as Mr.Sumit said you can have resting period of 7 days to 15 days between 100 days.

There is no side effect of Ashwagandha. It is also called as indian Ginseng. Ashwa means horse and gandha means smell. It is named so because the roots of it smells like horse urine. It has all quality of horse. Like horse never sits so it is used for stress (mentally and physically) . It is also aphrosiodic remedy. Immunity booster, natuaral pain killer. It should be consumed for 100 days and then 7 days gap is must.