This brings up a good question - what if it had been cocoa butter? What part of chocolate is poisonous to dogs?
They say all chocolate is poisonous to dogs, however, I have had two friends whose dogs ate chocolate on a regular basis and never became ill. I still don't trust that with my three! Being that cocoa butter is made from the cocoa bean, which is what chocolate is also derived from, I would/do take precautions with it around my dogs. I keep my cocoa butter in a hard container with a screw on cap on a shelf high above where my dogs can reach it. I have a Boston Terrier, Chihuahua mix, and a full blood Chihuahua, so all of mine are fairly small (under 20#), so keeping out of their reach is not difficult. It was much harder when we had our American Dingo (aka Carolina Dog) that was able to reach counter height items, so I kept it in a cabinet in a room that the dogs could not access.
As for coconut oil, that is actually very good in their diets for hair, nails, and other health benefits. Due to this, they DO get 1/4 - 1/2 tsp each (varies on their size...the full Chihuahua (7#) gets 1/4, and the other 2 get 1/2 each as they are 17 and 18 #'s. I give this to them every week, though it can be given daily. (I don't give daily because we cook with coconut oil and my husband is horrible about giving them scraps of his dinner against my every protest NOT to feed them from his plate). I will also make them their own food for the week and add coconut oil to that while it is still warm and before putting in their food container for in the refrigerator. So, in other words, the extra 1/4-1/2 tsp given during the week is just to ensure that they got the correct amount in their diets. It totally helps, especially if you have a dog with allergies that does a ton of scratching from any pollen, grass, corn, soy, or gluten in their diet.
it isn't fun... try having Danes (2) and both getting the runs.... in Winter time. 
