A ribosome infusion was a medical procedure in which ribosomes from one person are transferred to another.
It was required to find a match for suitable ribosomes in potential donors, often difficult but the compatibility could cross species. At least by the 24th century, common replicators could not produce them.
In 2366, Doctor Beverly Crusher attempted to convince Lieutenant Worf to agree to a ribosome infusion to treat the Romulan Patahk, who had suffered extensive cell damage and early neural pathway degeneration while on Galorndon Core, a planet with highly active and dangerous electromagnetic storms. Worf was the only compatible donor aboard the USS Enterprise-D, but refused to cooperate in assisting the Romulan and Patahk refused to accept assistance from a Klingon. (TNG: "The Enemy")