There are a number of religious prohibitions in Sikhism.
- Cutting hair: Cutting or removing hair from any body part is strictly forbidden for Amritdhari (formally baptized) Sikhs.
- Intoxication: Consumption of alcohol, drugs, tobacco, and other intoxicants is not allowed. Intoxicants are strictly forbidden for a Sikh.
- Blind spirituality: Superstitions and rituals should not be observed or followed, including pilgrimages, fasting and ritual purification; circumcision; idols, grave worship; compulsory wearing of the veil for women. Observation of the 5 K's, is not considered blind superstition.
- Material obsession: Obsession with material wealth is not encouraged in Sikhism.
- Sacrifice of creatures: Practices such as sati (widows throwing themselves on the funeral pyre of their husbands) and ritual animal sacrifice to celebrate holy occasions are forbidden.
- Non-family-oriented living: A Sikh is encouraged not to live as a recluse, beggar, yogi, monastic (monk/nun) or celibate.
- Worthless talk: Bragging, gossip, lying, slander, "back-stabbing", etc. are not permitted. The Guru Granth Sahib tells the Sikh, "Your mouth has not stopped slandering and gossiping about others. Your service is useless and fruitless."
- Priestly class: Sikhism does not have priests, as they were abolished by Guru Gobind Singh (the 10th Guru of Sikhism). The only position he left was a Granthi to look after the Guru Granth Sahib; any Sikh is free to become Granthi or read from the Guru Granth Sahib.
- Eating meat killed in a ritualistic manner (Kutha meat): Sikhs are strictly prohibited from eating meat killed in a ritualistic manner (such as halal or kosher, known as Kutha meat ), or any meat where langar is served. In some small Sikh sects, e.g. Akhand Kirtani Jatha eating any meat is believed to be forbidden, but this is not a universally held belief. The meat eaten by Sikhs is known as Jhatka meat.
- Having extramarital sexual relations
Violation of prohibitions
Not all people calling themselves Sikh subscribe to these prohibitions. The Sahajdhari Sikhs reject most of the prohibitions, including trimming of hair (Kesh). Some young Sikhs are now cutting their hair to the dismay of spiritual leaders. According to the Sikh clergy, "the fad among youth to shed the pagri" is being observed more commonly among the Sikh youth in Punjab than Sikhs in other Indian states.
Nihang Sikhs of Punjab, who are defenders of historic Sikh shrines, are an exception and consume an intoxicant called bhang (cannabis sativa), opium and other narcotics to help in meditation saying that it is puratan maryada (Punjabi for "old tradition"). Bhang is common in India; according to a legend, even the Hindu God Shiva was fond of bhang and it became his favourite food. In 2001, Baba Santa Singh, the Jathedar of Budha Dal, along with 20 Nihang sect chiefs, refused to accept the ban on the consumption of bhang by the highest Sikh clergy. Baba Santa Singh was excommunicated and replaced with Baba Balbir Singh, who agreed to shun the consumption of bhang.
The Udasis, who consider themselves as a denomination of Sikhism, lay emphasis on being ascetic, thus violating the "Non-family-oriented living" principle. Sri Chand, the ascetic son of Guru Nanak, was the founder of the Udasi.