Pan-assay interference compounds (PAINS) are chemical compounds that often give false positive results in high-throughput screens.
[1] PAINS tend to react nonspecifically with numerous biological targets rather than specifically affecting one desired target.
[2] A number of disruptive functional groups are shared by many PAINS.
[2][3][4] While a number of filters have been proposed and are used in virtual screening and computer-aided drug design,[5] the accuracy of filters with regard to compounds they flag and don't flag has been criticized.
[6] Common PAINS include toxoflavin, isothiazolones, hydroxyphenyl hydrazones, curcumin, phenol-sulfonamides, rhodanines, enones, quinones, and catechols.