Thank you Anders,
Just as in cats and dogs, chocolate is toxic to rabbits. The methylxanthines in chocolate can severe GI upset (appetite loss, diarrhoea), excessive thirst, urination, abnormal heart rhythm, tremors, seizures and death in our bunnies. Just to note, we often won't see signs of these issues until 2-4 hours post ingestion (the neurological signs can even be delayed 24 -36 hours). Therefore, we do need to monitor her closely and tread with care.
Now in dogs and cats, we induce vomiting in situations like this, but this is not possible in rabbits due to their stomach design. Therefore, our treatment at this stage would focus on binding the toxins in this chocolate. To do so, you can consider administering activated charcoal (LINK) available from the pharmacy to bind any remaining material in her stomach. For activated charcoal, we tend to give 1-4 grams per pound of her body weight every 8 hrs. This can be mixed with food or water to syringe feed (do note that it stains, so keep it away from white carpets/clothes). It works to bind the non-absorbed material and can limit the dose she has had.
Otherwise, it will be a case of monitoring her for the signs I mentioned and making sure that she doesnt' go off her food (since secondary gastric stasis is just as dangerous for Coco). As well since diarrhea is a risk here, do make sure she is offered increased fiber/hay and has access to fluids. If she develops diarrhea but doesn't drink well, you may need to syringe feed fluids to keep her hydrated.
Overall, chocolate is very dangerous for our rabbits. In this case, I am glad to hear that she is well so far but we are not out of the woods yet. Therefore, in Coco's situation, it'd be best to administer activated charcoal now to offset the risk here for her. If you cannot, then you may want to consider having your local vet do so +/- put her on IV fluids to flush this out of her system before it can do any harm. Otherwise, we need to closely monitor and provide symptomatic treatment should any of these signs arise.
In this situation, just in case you do wish to see an emergency vet, you can check HERE and @ http://www.vetlocator.com/.
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best, Dr. B.