ABSTRACT Background ThePhosphoinositide 3-kinases (PI3Ks) family plays a crucial role intumorigenesis. Alpelisib (inhibiting PI3Kα), copanlisib (inhibiting PI3Kα andPI3Kδ), duvelisib (inhibiting PI3Kδ and PI3Kγ), and idelalisib (inhibitingPI3Kδ) were developed to target the PI3K pathway. However, the toxicity limitstheir application to some extent. It’s necessary to investigate the adverseeffects (AEs) of these inhibitors. Research designand methods We conducted acomparative analysis of the safety signals of AEs in PI3K inhibitors usingdisproportionality analysis in the FDA Adverse Event Reporting System database(FAERS). Results Our studyidentified significant safety signals for metabolic disorders with all PI3Kinhibitors. Notable safety signals for gastrointestinal disorders were observedwith most PI3K inhibitors, with the exception of copanlisib. Common AEs shared amongall PI3K inhibitors included colitis and dehydration. Alpelisib displayedunique AEs associated with metabolic disorders, whereas copanlisib exhibitedidiosyncratic AEs linked to cardiac and vascular disorders. Stevens-Johnsonsyndrome emerged as a common severe adverse event (SAE) among alpelisib,copanlisib, and idelalisib, while febrile neutropenia was prevalent amongcopanlisib, duvelisib, and idelalisib. Intestinal perforation was solelyassociated with alpelisib. Conclusions The safety profiles of the five PI3K inhibitorsvary concerning adverse events. These findings could guide drug selection andinform future prospective research.