Abstract: Ashwagandha (Withania somnifera) is a well known herb possessing several health benefits. The steroidal lactones (withanolides) obtained from its roots have been implicated in a wide range of therapeutic activities and maintaining general health: Immunomodulation, combating infectious agents, anti-cancer and anti-epileptic, memory enhancer, to promote good physical and mental health, mood elevator, diuretic, general tonic and rejuvenator, stress reliever, cardiorespiratory endurance enhancer, anti-ageing, anti-oxidant, hypoglycemic, hypocholesterolemic and in common an effective adaptogen. Steroidal alkaloids and lactones are the active constituents of the plant. Withanolides as per theory occupies the receptor sites in the cell membrane thereby preventing the attachment and subsequent exertion of the effect of actual hormone. Withanolides have got analgesic and anti-inflammatory activity due to cyclooxygenase-2 inhibition property. Ashwagandha enhances nitric oxide synthatase activity of the macrophages, which in turn increases the microbial killing power of these immune cells thereby enhancing the Cell Mediated Immune (CMI) response. A glycoprotein Glycowithanolides (WSG) commonly known as W. somnifera glycoprotein is responsible for antimicrobial activity. Milk supplemented with Ashwagandha has been reported to increase total proteins and body weight and the plant alone helps in inducing tolerance and dependence. Its anti-stress and radiosensitization action; beneficial effects on cardiovascular system and sexual behavior; curative properties against neurodegenerative diseases and poisoning due to toxins and chemicals (including snake venom) has made this plant a treasure of nature. Thus the plant is an important component of many polyherbal preparations. Important for researchers and scientists is that biotechnologically advanced techniques; novel disciplines of bioinformatics and genomics can help in identifying and generating bioactive principles of the plant. All these salient health applications of this herb in biomedicine and veterinary sciences are discussed in this review focusing its potent role in maintaining sound health, immunomodulatory effects, combating infections, therapeutic usages and other beneficial applications.