My father 58 years old ate rice that were 2 days old. He is feeling nausea and doing vomiting since then. Also he produce diarrhea. I gave him metronidazole yesterday but still he is in same condition
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Bacillus cereus food poisoning old rice treatment metronidazole ineffective management 2024
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I now have a thorough picture from Harrison's (2025), Rosen's Emergency Medicine, and multiple microbiology textbooks. Here is a complete, evidence-based answer:
What Is Happening to Your Father
This is almost certainly "Fried Rice Syndrome" - food poisoning caused by Bacillus cereus, a spore-forming bacterium that thrives in cooked rice left at room temperature. It is one of the most well-documented causes of illness from day-old or improperly stored rice.
B. cereus produces preformed toxins that are already embedded in the food before it is eaten. This is the key reason why metronidazole is not helping - antibiotics cannot neutralize toxins that are already inside the gut.
Why Metronidazole Is Not Working
Metronidazole is the wrong drug here. Metronidazole works against anaerobic bacteria and protozoa (like Giardia, Trichomonas, C. difficile). It has no meaningful activity against Bacillus cereus, and more importantly, the illness is driven by preformed enterotoxins - not active bacterial infection. As Rosen's Emergency Medicine states directly: "Food poisoning is generally short-lived (24 h), and the treatment is typically supportive care only."
Stop the metronidazole - it is not indicated and won't help.
What B. cereus Food Poisoning Looks Like
According to Harrison's Principles of Internal Medicine (2025):
B. cereus causes two forms:
| Form | Incubation | Symptoms | Source |
|---|---|---|---|
| Emetic (vomiting) | 1-6 hours | Nausea, vomiting, some diarrhea | Fried/old rice, pasta |
| Diarrheal | 8-16 hours | Watery diarrhea, cramps | Meats, vegetables |
Your father likely has combined features (both vomiting and diarrhea) which is common. The illness typically resolves within 24-48 hours on its own.
What You Should Do Now
1. Oral Rehydration - Most Important Step
Vomiting and diarrhea cause dehydration, which is the main danger, especially in a 58-year-old.
- Give ORS (Oral Rehydration Salts) - available at any pharmacy (e.g., Electral, ORS sachets dissolved in 200 ml clean water)
- If he cannot keep fluids down, give small sips every few minutes - even 5-10 ml at a time
- Avoid plain water alone in large quantities - it lacks electrolytes
- Avoid milk, fruit juices, or caffeine
2. Symptomatic Relief
- For vomiting: Ondansetron (Ondem) 4 mg - oral or sublingual tablet - is safe and effective. Or domperidone 10 mg before meals.
- For diarrhea: Do NOT use loperamide (Imodium) if there is fever or blood in stool. Since there is no fever mentioned, a single dose can be considered cautiously.
- For cramps: Dicyclomine (Cyclopam) 20 mg can ease abdominal spasms.
3. Diet
- Nothing by mouth for 1-2 hours after vomiting, then slowly restart with:
- Plain rice (freshly cooked), banana, plain toast, boiled potato (the BRAT diet)
- Avoid spicy, fatty, or dairy foods for 2-3 days
4. Watch for These Warning Signs - Go to Hospital Immediately if:
- Signs of severe dehydration: no urination for 6+ hours, very dry mouth, sunken eyes, confusion, dizziness on standing
- Blood in stool (suggests a more serious infection like Salmonella, Shigella, or E. coli)
- High fever (>38.5°C / 101.3°F) - suggests invasive bacterial infection, not just toxin-mediated illness
- Symptoms not improving or worsening after 48 hours total from onset
- Chest pain, difficulty breathing, altered mental state
At the hospital, IV fluids (normal saline or Ringer's lactate) can be given if he cannot maintain oral hydration.
Important Note on Antibiotics
For straightforward B. cereus toxin-mediated food poisoning, no antibiotic is needed or effective. The Medical Microbiology textbook confirms: "Since gastroenteritis is short and uncomplicated, symptomatic treatment is adequate."
The only situation where antibiotics are used for B. cereus is in severe invasive disease (bacteremia, meningitis) in immunocompromised patients - which is not the case here.
Bottom Line
Your father has a self-limiting illness. The priority is:
- Hydration with ORS
- Antiemetics to control vomiting (ondansetron)
- Stop metronidazole - it is not helpful here
- Monitor closely for dehydration or any red-flag symptoms listed above
- Most patients recover fully within 24-48 hours of onset
If he is still vomiting heavily and cannot keep any fluids down, take him to a clinic or ER for IV fluids - that is the most effective intervention at that point.
Disclaimer: This is general medical information and not a substitute for evaluation by a licensed physician. If you are concerned about his condition, please consult a doctor in person.
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