The present invention provides: a drug delivery promoter for promoting the delivery of a drug for the treatment of diseases associated with angiodysplasia to an affected site, the drug delivery promoter containing as an active ingredient a substance that activates lysophospholipid receptors； a pharmaceutical composition for the treatment of diseases associated with angiodysplasia, the pharmaceutical composition containing as an active ingredient a substance that activates lysophospholipid receptors； and a method for screening drugs for the treatment of diseases associated with angiodysplasia, the method being characterized in that a substance that activates lysophospholipid receptors is selected, the substance being expressed specifically in vascular endothelial cells at the affected site.
