Here are some potential causes of these symptoms:
* Infections: Parvovirus, distemper, and other infectious diseases can cause vomiting, diarrhea, and lethargy.
* Food poisoning: Consuming spoiled food or toxic substances can lead to these symptoms.
* Parasites: Intestinal parasites like roundworms and hookworms can cause digestive issues.
* Gastrointestinal issues: Conditions like pancreatitis, gastritis, or inflammatory bowel disease can cause vomiting, diarrhea, and lethargy.
* Kidney or liver disease: These conditions can lead to various symptoms, including lethargy and digestive upset.
* Stress or anxiety: Dogs can experience stress-related vomiting and diarrhea.
* Medications: Certain medications can have side effects that include vomiting, diarrhea, and lethargy.
* Other causes: Heat stroke, dehydration, and poisoning can also cause these symptoms.
It's essential to seek veterinary attention as soon as possible to determine the underlying cause and receive appropriate treatment. Your vet will likely perform a physical exam, run diagnostic tests (e.g., bloodwork, fecal analysis), and may recommend further investigations like imaging or biopsies.
Please do not attempt to diagnose or treat your dog yourself. Prompt veterinary care is crucial for your dog's health and well-being.