It's been in the news lately about horse meat being disguised as beef.
Is this really that serious?
Is horse meat unsafe? Or is it just taboo because horses are "cute"?
It is perfectly safe to eat (when produced, transported, and so on under sanitary conditions, just like any other edible meat).
In some cultures it is considered a delicacy; in others, it is not considered appropriate to eat, but those issues of cultural norms, not of safety.
The news is because it is a violation of trust (truth in labeling) in a cultural background where horses are not normally eaten. Personally, I might wonder what other shortcuts the purveyor had taken if they are lying about content...
Adding to @SAJ14SAJ's answer, horse meat is perfectly fine for eating, but not if the horse has been treated with medicines that make it un-fit for human consumption.
Horses in the United States are not bred, raised or treated as meat. Almost all equine medications and treatments are labeled 'not for horses intended for human consumption.' In the European Union, horses intended for slaughter cannot be treated with many medications commonly used for U.S. horses.
It is produced and eaten in various countries. A bit of trivia - Icelandic people were reluctant to convert to Christianity for a long long time after Pope Gregory III banned horse meat consumption in 732 AD, because it was considered a Pagan thing to eat horse meat.
In the European Union, all horses must have a so called passport, which is a document that ensures that no forbidden medicinal products end up in the meat. When treating a horse, you can in some situations choose to use a drug that is approved for use in the food supply chain, but in some cases this is not possible. Keep in mind that horses will live 15–25 years.
If a horse has been treated with a forbidden drug, it is illegal to introduce it in the food supply chain (must not come into the slaughterhouse) and must be sent to destruction or be buried. The scandal in this case is that no one in the supply chain, except where it was wrongly marked beef, knew that it was horse meat and if it was approved for human consumption or not.
There is no mammal meat which is dangerous, with the exception of certain organ meats such as polar bear liver (which has toxic levels of vitamin A). The issue was with veterinary drugs which are not permitted for food use ending up in the food supply.