Atasi (Linum usitatissimum L.), known as flax, is a recommended drug in Ayurveda. The drug Atasi is used as an ingredient in many formulations used internally and externally for therapeutic purposes. The study aimed to critically review various aspects of the drug “Atasi” such as its synonym, classification, therapeutic properties, actions, and formulations from available classical texts of Ayurveda. Data on Atasi were collected from 13 Nighantu (lexicons), 14 Rasa/Yoga/sangraha grantha (compendia related to Rasa/Yoga/sangraha grantha) 5 Chikitsa grantha (compendia), and 10 Samhita (treatise). Atasi is a content of 86 formulations wherein 21 are used internally, 62 are externally, and 3 are for both purposes. Atasi-contained formulations are mentioned to manage a total of 30 diseases. Maximum formulations are noted in vataroga (neuromuscular anomalies) and the most common dosage form is kalka (paste). A total of 29 synonyms have been attributed to Atasi. It has Madhur (sweet), Tikta rasa (bitter taste), Guru (heavy), snigdha (unctuousness) Guna (attribute), Ushna virya (hot potency), and Katu vipaka (pungent bio-transformed rasa). Atasi is unwholesome substance in Raktapitta (bleeding disorder) and for consumption with parada (mercury) containing formulations. The present review may encourage further scope of scientific evaluation and validation of this medicinally important plant Atasi.