Self-anointing in animals, sometimes called anointing or anting, is a behaviour whereby a non-human animal smears odoriferous substances over itself. These substances are often the secretions, parts, or entire bodies of other animals or plants. The animal may chew these substances and then spread the resulting saliva mixture over their body, or they may apply the source of the odour directly with an appendage, tool or by rubbing their body on the source.

The functions of self-anointing differ between species, but it may act as self-medication, repel parasites, provide camouflage, aid in communication, or make the animal poisonous.

Several primate species self-anoint with various items such as millipedes, leaves and fruit. They sometimes drool while doing this. Both capuchin monkeys and squirrel monkeys perform urine washing, when they deposit a small quantity of urine onto the palm of a hand and then rub it on the sole of the opposite foot. It is thought to have multiple functions including hygiene, thermoregulation and response to irritation from biting ectoparasites (such as ticks and botfly). Some strepsirrhines and New World monkeys also self-anoint the body with urine to communicate.

Wild wedge-capped capuchin monkeys (Cebus olivaceus) self-anoint with millipedes (Orthoporus dorsovittatus). Chemical analysis revealed these millipedes secrete two benzoquinones, compounds known to be potently repellent to insects and the secretions are thought to provide protection against insects, particularly mosquitoes (and the bot flies they transmit) during the rainy season. Millipede secretion is so avidly sought by the monkeys that up to four of them will share a single millipede. The anointment must also involve risks, since benzoquinones are toxic and carcinogenic; however, it is likely that for capuchins, the immediate benefits of self-anointment outweigh the long-term costs. Secretions from these millipedes also elicit self-anointing in captive male and female tufted capuchin (C. apella) and white-faced capuchin (C. capucinus) monkeys.

Wild Cebus anoint more with plant parts, including fruits, whereas wild Sapajus anoint more with ants and other arthropods. White-faced capuchins in particular use more plant species at each site for anointing compared with other capuchins and may specialize in anointing as an activity independent from foraging, whereas most other capuchin species tend to eat the substances they use for anointing. Wild Cebus anoint at a higher frequency than Sapajus as occurs in captive groups. However, contrary data from captive animals there no difference in the range of sociality for anointing between Cebus and Sapajus in the wild.

Capuchin monkeys at the Edinburgh Zoo rub onions and limes on their skin and into their fur as an antiseptic and insect repellent.

White-faced capuchin monkeys sometimes anoint their bodies with mud and plant matter, a natural insect repellent. With their heads and faces slathered in this mixture, these highly social primates lose their ability to recognise each other and previously friendly monkeys can become fighting foes.

Mexican spider monkeys (Ateles geoffroyi) self-anoint with the leaves of three species of plants; the Alamos pea tree (Brongniartia alamosana), the trumpet tree (Cecropia obtusifolia) and wild celery (Apium graveolens). In one study, only two males in a group of 10 individuals displayed self-anointing. Only the sternal and axillary regions of the body were rubbed with the mix of saliva and plant material. There was a lack of correlation between the occurrence of self-anointing and time of day, season of the year, ambient temperature or humidity, indicating that this behaviour does not function in repelling insects and/or mitigating topical skin infections in this species. Rather, the three plant species spread an intensive and aromatic odour when crushed, indicating that self-anointing in Mexican spider monkeys may play a role in the context of social communication, possibly for signalling of social status or to increase sexual attractiveness.