Scurvy

Scurvy is a disease caused by inadequate nutrition, particularly from a lack of fruit and vegetable consumption. It is frequently suffered by pirates and other long-term sailors due to lacking fresh food onboard.

Overview
Once a person begins suffering from scurvy, their skin will turn pale and they will enter a comatose state. Victims will also have their teeth start falling out, and begin bleeding from old wounds.

The cure for scurvy is consuming fruits and vegetables again, and the best way to enable consumption is to get them to drink a fruit juice such as lime juice. The patient should then rest for a few days to fully recover. Upon being given lime juice to drink, Yosaku quickly regained his energy and started dancing, though his lack of rest caused him to quickly start bleeding and collapse again.

It appears that scurvy is common knowledge among well-informed sailors, and it is important for pirate crews to have a capable cook in order to make properly nutritious meals.

History
According to Nami, scurvy was the bane of sailors in the past, but its cause and cure were eventually discovered.

The bounty hunter Yosaku contracted scurvy while sailing with his partner Johnny. Johnny had no knowledge of what the illness was or how to treat it. However, he eventually crossed paths with the Straw Hat Pirates, and Nami had Luffy and Usopp give Yosaku lime juice to heal him.