Afflictions and illnesses

The following is a list of afflictions and illnesses shown in the series.

Cutie Pox
In The Cutie Pox, Twilight reads this description from a book: "This puzzling pony plague afflicted a population of ponies back in the Paleopony period. Random cutie marks appeared all over the ponies' bodies, causing them to be forced to perform, without stopping, all the talents that came with them. The cause of the breakout was never discovered, and the cutie marks disappeared as mysteriously as they arrived." The only case seen in the series is contracted by Apple Bloom after an overdose of Heart's Desire plant petals. It is cured by the Seeds of Truth supplied by Zecora, which sprout only in the presence of a truthful confession.

Feather Flu
A number of ponies contract Feather Flu in Hurricane Fluttershy. Initially Rainbow Dash accuses Thunderlane of trying to get of out of setting a new tornado speed record with all the other Pegasus ponies when she hears coughing. Afterward, Blossomforth, who was standing behind Thunderlane, is shown coughing. Later at least seven other Pegasi are reported to have contracted Feather Flu, at least one (Thunderlane) requiring a hospital stay. A cure is not mentioned, though Twilight's disinfectant spray does not seem to stop Thunderlane from having the Feather Flu.

Food poisoning
Food poisoning is seen in Applebuck Season when Pinkie Pie accidentally serves "Baked Bads" after Applejack's sleep-deprived attempts to help with muffin baking go awry. Nurse Redheart tends to a number of ponies who are seen squirming and writhing on their beds, many of them green-faced; some of them vomit.

Hay Fever
In The Cutie Pox, Twilight mentions that she had been reading about "unusual equine illnesses" in a book entitled 'Perplexing Pony Plagues'. One of the illnesses she mentions is Hay Fever, though she gives no details about it.

Pony Pox
Fluttershy pretends to be afflicted with Pony Pox in Hurricane Fluttershy in an attempt to avoid Rainbow Dash's recruitment efforts toward setting a new tornado speed record. Pony Pox may or may not be a real affliction; Fluttershy's faked symptoms include sneezing, coughing, and being covered in red spots. Rainbow Dash "cures" Fluttershy by dousing her with water, causing the fake red spots to wash off.

The Trots
In The Cutie Pox, Twilight mentions that she had been reading about "unusual equine illnesses" in a book entitled 'Perplexing Pony Plagues'. One of the illnesses she mentions is The Trots, though she gives no details about it.

The Common Cold
In Winter Wrap Up, Spike gets a cold after falling into cold water, although his only noticeable symptom is sneezing. During the song in Hearts and Hooves Day, Sweetie Belle remarks that one of Cheerilee's potential suitors has a terrible cold, who acknowledges her by sneezing.

Poison joke
Poison joke, which appears in the episode Bridle Gossip, is a magical plant that causes ridicule-inducing afflictions on the six main ponies who come into contact with it.

In the episode, the ponies accidentally stumble into a large patch of poison joke despite warnings from Zecora. The plant has large leaves with a multi-petaled bulb sticking out of the center, each bulb sporting a few stamen. The entire plant is blue, including leaves and stalk, with dark streaks running over it in a design.

Like its namesake, poison oak, it affects the ponies after they merely come into contact with it, but as described by Zecora, the plant does not poison its victims; rather, it plays practical jokes, which manifest as physical afflictions. The jokes in the episode magically match the victim's personality and traits.

In the episode, the ponies are afflicted with the following:
 * Twilight Sparkle's horn becomes limp and covered in blue spots.
 * Rainbow Dash's wings become inverted, where the wings are upside down and on her stomach area.
 * Applejack shrinks down to a tiny size and can fit on a pony's hoof.
 * Rarity's mane, coat, and tail become frizzled, very long, and mop-like.
 * Pinkie Pie's tongue becomes swollen and covered in blue spots, keeping her from being able to speak intelligibly.
 * Fluttershy's voice deepens into that of a man with an African-American accent.

The effects of poison joke are eventually cured by taking a herbal bath for which the recipe is found in a book called Supernaturals: Natural Remedies and Cure-Alls That Are Simply Super, which Twilight initially ignored in the episode because of the first part of its title.

Allergies
During the episode Bridle Gossip one of the possible causes Twilight Sparkle considers to explain what turns out to be the effect of Poison joke is an allergic reaction.

Stone
In the episode Stare Master, a cockatrice demonstrates the ability to turn ponies and chickens to stone with its gaze. It does so to Twilight Sparkle and Elizabeak and starts to do so to Fluttershy, but she resists its effects and intimidates it into turning Twilight and Elizabeak back to normal.

At the beginning of the episode The Return of Harmony Part 1, Discord, having been turned to stone by Princess Celestia and Princess Luna using the Elements of Harmony long beforehand, escapes after the Cutie Mark Crusaders get into a fight in front of his stone form. Celestia explains that the spell to keep Discord contained broke due to her and Luna no longer being connected to the Elements. At the end of the episode The Return of Harmony Part 2, the six main ponies use the Elements to turn Discord back to stone.

Paralysis
In one of the comics in the German magazine, Twilight Sparkle, Applejack, and Spike discover Pinkie Pie and Fluttershy appearing to be petrified. Twilight reads in a book that when ponies are looking forward to something so much that they can't take the anticipation, they might get paralyzed. She tells Applejack and Spike that the cure is a special cereal with a smell that calms them down so they can wake up, and that this cereal doesn't grow anywhere in Equestria, only being found beyond the Everfree Forest. After traveling to a barley field outside of Equestria, the three of them return to Ponyville with some of the barley and make a campfire with it, which wakes up the paralyzed ponies.