Sickness is a status condition in which the player's Tamagotchi becomes severely ill, and the user must respond quickly to return the Tamagotchi to normal health. It was introduced on the original Tamagotchi, and has appeared on almost every release since.
The standard sickness is portrayed by a skull floating next to the Tamagotchi, with the Tamagotchi looking upset. The Tamagotchi will refuse to eat food, play games, or use any items, though the user may still use the Meter and Flush icons. The user must use the Medicine icon (or, on later releases, the Clover icon) to restore the Tamagotchi to normal, but must do it within a limited time frame. Failing to respond in time may cause early Death. Multiple doses may be required to help the Tamagotchi recover.
The medicine icon is usually represented by a syringe or a bottle of medicine, both implied to be the tools used to administer the remedy. On most video games the player has a choice between an injection or orally-taken medicine, and certain species recover quicker with one option rather than the other. On the Yasashii Tamagotchi, one of the two functions of the care button is to help a Tamagotchi when it is sick and pressing it to do so will show an animation of the Tamagotchi wrapped in a warm blanket to recuperate.
On vintage releases, a Tamagotchi naturally falls ill close to its time of evolution. For the baby stage, this is typically within 20 minutes. For all other stages, it may be anywhere between 12 and 24 hours. Sickness can also be deliberately induced through neglect, by leaving Hungry or Happy hearts empty long enough to obtain a care mistake or letting poo occupy the screen for too long. On certain modern releases, the attention icon will not turn back on if a heart-related care mistake causes the Tamagotchi to get sick. On the Tamagotchi Ocean, these sorts of illnesses tend to occur daily for a growing Tamagotchi.
On the original Tamagotchi, the Tamagotchi would also spontaneously become sick as it aged. If the user is able to keep it alive past the age of 10, it will become sick at the age of 12, and get sick again every three days (15, 18, etc.). Each time it gets sick, its hearts will drop faster than they previously did, until the Tamagotchi eventually dies.
On the Tamagotchi Angel, the Angel would never get sick unless the user turns off the lights while the Angel is awake. Doing this too many times would trigger it to mutate into Deviltchi, though this occurs more often for immature Angels than it does for adults.
On the Tamagotchi Connection Version 1, skulls can be sent as negative connection gifts and receiving one will cause a Tamagotchi to become sick (but won't gain a Care Mistake).
On the Entama, Hanerutchi 2 and Uratama, cough drops obtained from the device's website can be used to lower the chance of a Tamagotchi getting sick upon a care mistake occurring.
On the color Tamagotchis, the screen fades to a translucent dark blue gradient when the Tamagotchi becomes sick.
Babies will also become sick on two occasions on color Tamagotchis as opposed to once on other releases, likely to make up for the lack of a period where both parent and child are raisable compared to previous releases - babies would normally become sick halfway through the period where both are present. On most modern releases babies show smaller skulls, known as "baby bugs".
One skull will appear on the screen at one time. So far, the only situation where more than one is seen is when an adult Tamagotchi has a baby and gets sick, and its baby becomes sick before the parent is cured. This can also happen in reverse.
Injury is a variation of sickness that occurs exclusively on the Tamagotchi Ocean and the Mori de Hakken! Tamagotch. For this variation, the Tamagotchi only becomes sick when the user fails to prevent a predator attack. Like a standard illness, repeated injuries can lead to a shorter lifespan and death. As a general rule, four injuries in a growth stage results in death.
On the Tamagotchi Ocean, it is represented by a skull. On the Morino, it is represented by the Mushitchi completely encased in a cocoon of bandages, leaning on a crutch with only its eyes visible. The sprite for every character injured is the same, with the exception of the two secret characters, Twinaritchi and Helmetchi, who have their own unique sprites.
Toothaches, also known as Cavities, were first seen on the original Tamagotchi, and have appeared on almost all modern releases, alongside the normal sickness. It occurs if a Tamagotchi eats fifteen consecutive snacks in a short period of time. The image for this sickness is represented by a broken tooth, though it was represented by the standard skull on the original Tamagotchi. Since the 2004 reboot, babies (and adults, prior to the Tamagotchi m!x) cannot get toothaches.
On the vintage era video games Tamagotchi have drastically lower tolerances for cavities, gaining them if just two or three snacks are fed over a several in-game hour period, and in the Game Boy games they can very easily be killed by just a couple of cavities across their life.
Sulking (known as Downheartedness in Japanese releases) is a negative status condition which is featured on every color Tamagotchi starting with the Tamagotchi iD. It also appears on the Tamagotchi Nano and its variants. It happens when an adult gains a Care Mistake and replaces the skull. It is represented by three vertical lines, one of which is longer than the others, and the Tamagotchi looking upset or facing away. On the Tamagotchi 4U and 4U+, child characters can sulk as well as adults, and only occur when the user misses a care call for an empty happiness bar. If allowed to sulk for too long, the Tamagotchi may get angry and run away.
A similar condition can occur on the Osutchi and Mesutchi when a call for discipline or low happiness is ignored. The Tamagotchi will not eat food while it is sulking, and will slouch in the middle of the screen without moving. It will go back to normal on its own devices for a while or if fed a snack or played with - doing the latter two will not increase happiness until the Tamagotchi is no longer sulking.