Medical Crates are a trade-good item in Windrose, looted from land-based points of interest and some enemy encounters. They are sold to faction traders for Piastres. Medical Crates are moderate in value, similar to Naval Supplies but sourced differently.
Source
Pirate camps - supply crates and guarded chests
Dungeons - loot rooms and boss areas
Abandoned camps and ruins - surface-level loot
Some shipwrecks in non-repairable condition
Use
Sold to faction traders. Medical Crates do NOT unlock any healing recipes or crafting paths even though the name suggests medical contents. They are a pure trade good. Keep them in dedicated trade-good storage alongside Naval Supplies and Contraband rather than mixing with consumables or alchemy ingredients.
Tactical Note
Medical Crates and Naval Supplies are often looted in similar volume from the same source (a cleared pirate camp or ship). The community rule of thumb is to sell both to whichever trader is closest when inventory space becomes a concern. Contraband is the only trade good worth saving specifically for Tortuga.
See Also
Trading and Merchants - trading overview
Naval Supplies - another moderate trade good
Contraband - high-value trade good
Pirate Camps - primary loot source