The Ashvins or Ashwini Kumaras (Sanskrit: अश्विन, aśvin-, dual aśvinau), in Hindu mythology, are two Vedic gods, divine twin horsemen in the Rigveda, sons of Saranyu, a goddess of the clouds and wife of Surya in his form as Vivasvant. They symbolise the shining of sunrise and sunset, appearing in the sky before the dawn in a golden chariot, bringing treasures to men and averting misfortune and sickness. They are the doctors of gods and are devas of Ayurvedic medicine. They are represented as humans with the heads of horses. In the epic Mahabharata, King Pandu's wife Madri is granted a son by each Ashvin and bears the twins Nakula and Sahadeva who, along with the sons of Kunti, are known as the Pandavas. Their marriage is an example of polyandry in the Rigvedic period.
They are also called Nasatya (dual nāsatyau "kind, helpful") in the Rigveda; later, Nasatya is the name of one twin, while the other is called Dasra ("enlightened giving"). By popular etymology, the name nāsatya is often incorrectly analysed as na+asatya "not untrue".
Indian holy books like the Mahabharat and the Puranas, relate that the Ashwini Kumar brothers, the twins, who were Raja-Vaidya (Royal Physicians) to Devas during Vedic times, first prepared the Chyawanprash formulation for Chyawan Rishi at his Ashram on Dhosi Hill near Narnaul, Haryana, India, hence the name Chyawanprash.
The Ashvins can be compared with the Dioscuri (the twins Castor and Pollux) of Greek and Roman mythology, and especially to the divine twins Ašvieniai of the ancient Baltic religion.
The Ashvins are mentioned 376 times in the Rigveda, with 57 hymns specifically dedicated to them: 1.3, 1.22, 1.34, 1.46-47, 1.112, 1.116-120 (c.f. Vishpala), 1.157-158, 1.180-184, 2.20, 3.58, 4.43-45, 5.73-78, 6.62-63, 7.67-74, 8.5, 8.8-10, 8.22, 8.26, 8.35, 8.57, 8.73, 8.85-87, 10.24, 10.39-41, 10.143. The Nasatya twins are invoked in a treaty between Suppiluliuma and Shattiwaza, kings of the Hittites and the Mitanni respectively.