Now that we have solved the practical problem, that is, we have washed the rabbit, we need to understand what caused the trouble. Usually, rabbits do not suffer from diarrhea. However, the feces you found are certainly a residue of undigested cecotropes. If you have had a rabbit for a while, you may have noticed that there are different types of feces. You may be used to seeing dry pellets, which you usually remove from the litter box. But you should know that there are also nutrient-rich feces that your rabbit eats immediately after elimination and are an integral part of its diet: cecotropes.
When this feeding cycle is disrupted, your rabbit does not eat cecotropes. The cause is usually a diet poor in fiber. Does your rabbit have unlimited access to fresh hay every day? This is, in fact, the basic food of its diet, as it is rich in fiber. Fibers keep your rabbit’s teeth well filed and its digestive system healthy.
You should not overfeed your rabbit with fruit, bread, or junk food that may make him happy at the moment but complicate the situation. For a correct diet and a complete list of what can be given to your rabbit, I recommend reading
What does a dwarf rabbit eat.