A villager that is sick will stay inside their house. Purple and black swirls (which can also be seen when a villager is sad or upset during a conversation with the player or another villager) appear around their heads as they walk. They are likely to shiver when they stand still. When the player speaks to the villager, an extra conversation option appears that lets the player offer them some medicine. If the player gives the villager a dose of medicine, they are grateful and will give the player a gift once they've recovered. Sometimes it will take multiple doses of medicine to cure their sickness, but only one medicine can be given to the same villager per day.
If the player accidentally shakes a wasp nest/beehive out of a tree, a swarm of wasps/bees will appear and chase the player. One way to outrun the herd of bees is to find the nearest building before they can get to the player. If stung, there will be a hive-shaped wound on the right section of the player's eye. The sting can be hidden with sunglasses or a Mii Mask. Without the medicine, the sting will heal within a day. Medicine can be used to cure the sting; however, saving the game and restarting has the same effect without the need to spend 400 Bells.
In New Leaf
Medicine is not available in stores initially. Nookling Junction must be upgraded before the player can purchase medicine. If stung by a bee, and the player talks to a villager, there is a chance that they would receive medicine, especially from certain villager types.
In New Horizons
Medicine can be obtained as a DIY recipe after the player is stung by wasps and talks to any villager they encounter. They will give the player the recipe which requires 1 wasp nest and 3 clumps of weeds to craft one medicine. After Nook's Cranny is upgraded the player can buy medicine from the cabinet individually or in bulk. Like in previous games, Medicine can be given to sick villagers where the player may receive a gift in exchange.