2', 3'-Dideoxyinosine (ddI) is in clinical trial as an anti-HIV agent. This unit is following the clinical pharmacology of this compound. Intravenously administered ddI has a half life of 38 minutes. ddI is very acid labile; therefore for the Phase I clinical trials the compound was given to fasting patients along with an oral antacid. The average oral bioavailability of this preparation was 38%. Other oral dosage forms were investigated to find a more convenient preparation and/or one with better bioavailability. The potential of interaction of ddI with ganciclovir and ranitidine was also investigated. It was determined that ddI had pharmacokinetic properties amenable to long term administration.