The situation where a dog has bloody stool but is in good spirits may be due to a variety of reasons. Some of the possible causes include: 1. Food problems: The dog may have eaten some inappropriate food, causing gastrointestinal discomfort and blood in the stool. You can try to adjust your dog's diet, such as changing to a lighter and easier-to-digest dog food, or giving your dog some probiotics to regulate his stomach. 2. Perianal damage: If the dog’s perianal area is damaged, blood may also appear in the stool. You can check whether the dog's perianal area is damaged. If it is damaged, treat it in time to avoid infection.

3. Parasitic infection: The dog may be infected with parasites, such as hookworms and tapeworms Etc., these parasites may cause blood in your dog’s stool. In this case, the dog needs to be dewormed in time.

4. Foreign body ingestion: The dog may have ingested sharp foreign bodies, such as fish bones, glass fragments, etc. These foreign bodies may damage the dog's intestines and cause blood in the stool.