Fourth among the vedas. It contains many mantras to harm enemies. It was written by Vasishta’s son Adharvana. According to Vishnupurana Ansh 3 Chapter 6, this veda was first taught by the very powerful sage Sumantu to his disciple Kabandha. Sumantu was the son of Vyasa’s disciple Jaimini. Kabandha split the veda into two and gave it to to sages named Devadarsha and Padhya.  Devadarsha’s disciples were Medha, Brahmabali, Shaulkayani and Pippaladan while Padhya’s were Jabali, Kumudadi and Shaunaka. Shaunaka, in turn, split it further and gave it to Babhru and Saindhava. Munjikesha received it from Saindhava and split it first into two, and then three parts. His works Nakshatrakalpa, Vedakalpa, Samhitakalpa, Aangirasakalpa and Shantikalpa are part of the Adharva veda. The Nakshatrakalpa has the kriyas of Brahma, the Samhitakalpa contains mantras, the Aangirasakalpa has rituals and the Shantikalpa has Ashvagajadi shantis. Following are the Adharva veda mantras and their uses

Suparnastva – removing snake venom

Indrenadatta – fulfilling desires of lust

Imadevi – peace

Devamaruta – peace

Yamasyalokal – ending bad dreams

Indrashchapanchavanija/ Indranjapanchavanija – gains in business

Kamojevaji – rise in fortunes relating to women

Thubhyamevajaveeman – equal to an ayuta sacrifice

Agnegobhinna – increasing intelligence

Dhruvamdhruvena – gains in position

Alaktajeeva – gains in agriculture

Ahantebhagna – rise in good fortune

Ye me pasha – freedom from imprisonment

Shapatvaha – destruction of enemies

Twamuttama – rise in fame

Yadhamrigavati – luck with women

Yenapehadisham – pregnancy

Ayatneyoni – for becoming parents

Shivashivabhi – increase in good fortune

Brihaspatirna Paripatu – fortune in travel

Munjavitva – stalling death

The most important ingredient in the rituals to be carried out while using these mantras are the bark of trees. Also important are ghee, grains, mustard, curd, milk, lotus flowers etc. More details in Agnipurana Chapter 262.