Health is measured by a bar next to the energy bar in the bottom right corner of the user interface (UI). The health bar is only visible while inside of The Mines, the Secret Woods, the Slime Hutch, the Skull Cavern, the Mutant Bug Lair, the Quarry Mine, or when the meter is not full. Outside of the Mines, the most common ways to lose Health are by getting hit by the train on the Railroad, or by the Slimes in the Secret Woods or in the Slime Hutch.
Health can be replenished either by consuming food, sleeping, using the Spa, or eating Stardrops. In a multiplayer game, Health (and Energy) can be replenished by standing in bed without going to sleep for the day.
Finding Secret Note #10 and then meeting Mr. Qi at level 100 of the Skull Cavern will award the player with a cutscene in which Mr. Qi gives the player "Iridium snake milk", which permanently increases Health by 25 points.
The player will pass out when health reaches zero. One of the villagers will awaken the player. Depending on which one it is, the player may wake up in the entry room of the mine, in the bedroom of the farmhouse, or in Harvey's Clinic. If the player passes out inside the Skull Cavern, he/she will be awakened inside Harvey's Clinic.
While passed out, the player will lose gold and inventory items. One lost item can be retrieved through the "Item Recovery Service" at the Adventurer's Guild. The amount of gold lost is determined by the player's currently available gold, up to 5,000g.