My Dog Is Lethargic,but Alert,not Drinking Or Eating, Can You Help?

Since long your dog is lethargic and has not eaten. If 24 hours are gone with this condition then it is time to visit a vet because this can be due to some underlying cause. Most common causes can be

   1. Electrolyte imbalance
   2. Anemia
   3. Infections
   4. Toxic reactions
   5. Cardiovascular disorders
   6. Hormonal disorders
   7. Cancer
   8. Skin and eye diseases
   9. Side effects of medicines
  10. Immune diseases

There can be more reasons but exact cause can be diagnose by your vet, so, take your dog to vet for this purpose.