Dog appeasing pheromone (DAP), sometimes known as apasine, is a mixture of esters of fatty acids released by the sebaceous glands in the inter-mammary sulcus of lactating female dogs. It is secreted from between three and four days after parturition and two to five days after weaning.^[1] DAP is believed to be detected by the vomeronasal organ (Jacobson's organ)^[1] and has an appeasing effect on both adults and pups,^[1] and assists in establishing a bond with the mother.^[2]

Synthetic DAP analogues have been developed which may support dogs during some, but not all, stressful situations.^{[3][4][5][6][7]}

Synthetic DAP analogues have been developed (e.g. "Adaptil"^[7]); however, there is mixed evidence for the efficacy of synthetic DAP in reducing stress-related behaviours.^[8][9]

Synthetic DAP can be effective at reducing stress-related behaviours in a number of contexts^[10] including puppies enrolled in socialization classes.^[11] A double-blind, placebo-controlled study found that newly adopted puppies aged 6 to 10 weeks cried less when exposed to synthetic DAP, but only in gun-dog breeds.^[12] It has been found to be highly effective in fear behaviours relating to sound sensitivity and fear of noises (e.g. fireworks and thunder).^[2]

Synthetic DAP is ineffective for dogs housed in long-term kenneling facilities^[10] and does not reduce soiling behaviour in newly adopted puppies.^[12]

In 2014, a critical review of studies on the use of synthetic DAP in veterinary hospital wards concluded that there was "little or no robust evidence" of it being effective in this environment.^[7]