Valentine's Day

Flowers - Many types for flowers and plant that are found in bouquets are harmful to pets.

Chocolate - Many people do not realize that chocolate can be a poison. Unsweetened baking chocolate carries a much higher dose of the toxin "theobromine" than does milk chocolate, but even normal milk chocolate can be dangerous; a small dog sharing candy can wind up in big trouble. Clinical signs of chocolate poisoning include hyperexcitability, nervousness, vomiting, and diarrhea and death. 

Easter

Fake grass - This colorful "grass" may look appetizing to your pet, but actually poses a choking and intestinal obstruction hazard if ingested.

Small toys and other plastic items - If swallowed, small toys and plastic Easter eggs can cause your pet to choke or even damage their intestinal tract.

4th of July

Fireworks - Fireworks not only scare pets and cause them to run off, but they can also cause serious injuries is detonated near your pet.  Many formulations can be potentially toxic to pets if ingested as well.

Dietary Indiscretion - We all like to include our pets in Holiday meals along with the rest of the family, but try to keep in mind that sudden diet changes are likely to upset a pet's stomach. Vomiting and diarrhea are not uncommon. If leftovers are of an especially fatty nature, the pancreas may become inflamed and overloaded. This condition is serious and may require hospitalization.

Halloween

Pranks - Some pets, specifically black cats, have become victims of torture and abuse during Halloween, so be sure to keep your pet indoors.

Candles - Pets are naturally curious, and may be attracted to the bright lights of the flame in dark areas. Dogs and cats could eith burn themselves by the flame or knock the candle over, starting a fire.

Xylitol - Candy or gum sweetened with xylitol is toxic and should be kept away from your pet.

Thanksgiving

Bones - Turkey, chicken and other small animal bones are very different from the large bones you find at the pet store. These small bones splinter easily and can cause serious internal damage if swallowed, so NEVER give them to your pet.

Christmas

Ribbons and Tinsel - These are of special interest to playful cats and kittens who see these materials as toys (or prey) to be chased, pounced upon, chewed or swallowed. While chasing and pouncing pose no health threats, chewing and swallowing do, as these strings or "linear foreign bodies" can catch in the GI tract, leading to bunching of intestine as the body tries in vain to move the string or ribbon through. This is a life-threatening condition requiring surgery for correction. Supervise animals who play with string closely.

Electric light cords -  These are also tempting to cats who like to play with string as well as to puppies who are teething and interested in chewing. If a pet bites through an electrical cord, it could result in a severe burn to the tongue which causes the pet's lung to fill with fluid, causing respiratory distress. This is also an emergency requiring immediate veterinary attention.

Christmas tree water - Stagnant tree water or water containing preservatives could result in stomach upset if ingested.

Batteries -  Batteries contain corrosives. If ingested they can cause ulceration to the mouth, tongue, and the rest of the gastrointestinal tract.

New Year's

Alcohol - Alcoholic beverages are toxic to pets and should NEVER be given to your cat or dog.

Balloons and confetti - These are among the common items used to decorate a New Year's party venue, but can pose an obstruction or choking hazard to your pet if ingested. Be sure to keep an eye on them when they are around these items or place them in an area that does not have decorations.