A vidicon tube‐based optical multichannel analyzer (OMA) was interfaced to a minicomputer to facilitate the acquisition of real‐time light transmission (or fluorescence anisotropy), right‐angle scattering, and fluorescence spectra at subsecond rates. The apparatus was designed for kinetic studies of the optical responses of living cells to stimulation with physiological and other activators, and features menu‐driven interactive graphics for presentation and handling of the intensity, wavelength, and time data in two or three dimensions. Stimulus‐induced secretion of acriflavine‐loaded human blood platelet dense granule contents is shown as an example of the apparatus capabilities.