released for use. These compounds can often be analgesic or antiparasitic in nature. In regards to an insect repellant, the secondary metabolites traditionally used by plants to deter herbivores and insects from eating them can be used by animals as a protective measure. By interfering with neuroreceptors, these secondary metabolites can specifically act as olfactory cues for insects to avoid a certain source. Methods of self-medication The three reported methods of self-medication are deglutition, ingestion, and topical application. When using one of these methods while appearing well, an animal may be using self-medication as a prophylactic measure. When it is unwell, the animal could be using self-medication as a curative measure. Deglutition Some examples of zoopharmacognosy are demonstrated when animals, namely apes, swallow materials whole instead of chewing and ingesting them. Chimpanzees Wild chimpanzees sometimes seek leaves of the Aspilia plant. These contain thiarubrine-A, a chemical active against intestinal nematode parasites. Because this compound is quickly broken down by the stomach, chimpanzees will pick up the Aspilia leaves and, rather than chewing them, they roll them around in their mouths, sometimes for as long as 25 seconds. They then swallow the capsule-like leaves whole. Afterwards, the trichomes of the leaves can attach to any intestinal parasites, namely the nodular worm (Oesophagostomum stephanostomum) and tapeworm (Bertiella studeri), and allow the chimpanzee to physically expel the parasites. As many as 15 to 35 Aspilia leaves may be used in each bout of this behaviour, particularly in the rainy season when there is an abundance of many parasitic larvae that can cause an increased risk of infection. Chimpanzees sometimes eat the leaves of the herbaceous Desmodium gangeticum. Undigested, non-chewed leaves were recovered in 4% of faecal samples of wild chimpanzees and clumps of sharp-edged grass leaves in 2%. The leaves have a rough surface or sharp-edges and the fact they were not chewed and excreted whole indicates they were not ingested for nutritional purposes. Furthermore, this leaf-swallowing was restricted to the rainy season when parasite re-infections are more common, and parasitic worms (Oesophagostomum stephanostomum) were found together with the leaves. Bonobos sometimes swallow non-chewed stem-strips of Manniophyton fulvum. Despite the plant being abundantly available all year, M. fulvum is ingested only at specific times, in small amounts, and by a small proportion of bonobos in each group, demonstrating that it is indeed only utilized when the bonobos are unwell. Monkeys Tamarins were observed