Why Farts Smell (and Sometimes Smell Like Rotten Eggs)
Gas smells mainly because gut bacteria break down food and release tiny amounts of sulfur compounds. Sulfur = "rotten egg" vibe.
Everyone has this. Stronger smell does not automatically mean infection, disease, or that you're gross.
Related: Short-Term Helpers (simple fixes) · Low-FODMAP Snacks (safer options) · What is FODMAP? (quick primer).
Why some gas smells stronger than other gas
- High-sulfur foods like eggs, garlic, onions, broccoli, cabbage, and other cruciferous veggies (think broccoli, cauliflower, Brussels sprouts, kale, cabbage) can drive sulfur smell.
- Constipation / feeling backed up. Poop sits longer = stronger smell because bacteria have more "fermentation" time.
- Big, rich dinner → you lie flat → digestion slows → gas sits. Morning = "explosion."
Try earlier dinner (like 2–3 hours before bed), lighter portions at night, or a short walk after eating.
"Rotten egg" smell specifically
The "rotten egg" thing is almost always sulfur. One common sulfur gas is hydrogen sulfide — same family as what makes eggs smell eggy. Strong egg smell after egg-heavy meals, garlic-heavy meals, or broccoli/cauliflower dinners is extremely common.
If you also have severe belly pain, fever, vomiting, black/tarry stool, blood in stool, or sudden major change in poop — that's when you call a medical professional. Otherwise, sulfur alone usually = food + timing.
Try a 7-day smell check (no shame version)
Goal: figure out if certain meals + timing = louder smell. Not to ban foods forever — just to spot patterns.
- Days 1–2: Keep your usual meals. Jot one quick line in your notes app each day: what you ate + how strong the smell was + how your belly felt (fine / pressure / bloated / pain score).
- Days 3–5: Change only one thing:
- Skip eggs at night and have them earlier in the day instead.
- Use garlic-infused oil instead of raw chopped garlic or big onion chunks (infused oil gives flavor with less of the tough carbs/sulfur heavy bits that some guts complain about).
- Shrink portions of cruciferous veggies (broccoli, cabbage, Brussels sprouts, cauliflower) instead of dumping them completely.
- Days 6–7: Re-add the thing you changed (like eggs at dinner again, or larger broccoli portion) and compare notes. If smell spikes back up and you feel more pressure, you just found one lever you can dial, instead of "my whole body is broken."
"Pat" ate a late burrito loaded with garlic and onion. By morning, they were convinced they had a gut infection. A few slower meals and earlier dinners later, smell dialed down. The culprit was timing + high-sulfur food stacking, not disease.
Reminder: this is general info, not personal medical advice. Talk to a clinician if you have severe pain, fever, blood in stool, black/tarry stool, or fast, unexplained weight loss.