The earliest classical Sanskrit works on Ayurveda describe medicine as being divided into eight components (Skt. aṅga). This characterization of the physicians' art, "the medicine that has eight components" (Skt. cikitsāyām aṣṭāṅgāyāṃ चिकित्सायामष्टाङ्गायाम्), is first found in the Sanskrit epic the Mahabharata, c. 4th century BCE. The components are:
Kāyachikitsā: general medicine, medicine of the body
Kaumāra-bhṛtya (Pediatrics): Discussions about prenatal and postnatal care of baby and mother, methods of conception; choosing the child's gender, intelligence, and constitution; and childhood diseases and midwifery.
Śalyatantra: surgical techniques and the extraction of foreign objects
Śhālākyatantra: treatment of ailments affecting ears, eyes, nose, mouth, etc. ("ENT")
Bhūtavidyā: pacification of possessing spirits, and the people whose minds are affected by such possession
Agadatantra/Vishagara-vairodh Tantra (Toxicology): It includes subjects about epidemics, toxins in animals, vegetables and minerals. It as well contain keys for recognizing those anomalies and their antidotes.
Rasāyantantra: rejunavation and tonics for increasing lifespan, intellect and strength
Vājīkaraṇatantra: aphrodisiacs and treatments for increasing the volume and viability of semen and sexual pleasure. It also deals with infertility problems (for those hoping to conceive) and spiritual development (transmutation of sexual energy into spiritual energy).