This nursing case study discusses the diagnosis and treatment plan for a 75-year-old male patient suffering from bacterial gastroenteritis. The patient had been experiencing symptoms like weight loss, high fever, vomiting, abdominal pain, and bloodied stool. The differential diagnosis included bacterial gastroenteritis, Helminthic infections, and Giardia infection. The stool microscopy and culture test confirmed bacterial gastroenteritis, and Yersinia enterocolitica was discovered to be the causal pathogenic organism. The treatment plan included rehydration therapy, antiemetics, antibiotics, and a BRAT diet.