The objective of this work was to develop a galenic form of activated charcoal appropriate for the needs of clinical toxicology. To preserve the adsorption capacity of charcoal, we developed an extemporaneous preparation of activated charcoal intended for clinical toxicology. To improve the wettability of activated charcoal, we used densification by wet granulation. The presence of a viscosity agent is necessary to ensure the homogeneity of the suspension and its adhesiveness on gastric mucous membrane. Five formulations with different viscosity agents were prepared, and their adsorption capacity, wettability, viscosity, and adhesiveness were studied.