When you swallow a seed, most seeds pass through your digestive system without causing harm. Many people believe that swallowing certain seeds, especially pepper seeds, can lead to appendicitis, but this is actually a myth.
Stomach acid and enzymes
Once swallowed, the seed moves down the oesophaguss to the stomach. The digestive acids and enzymes in the stomach will start to break down some of the seed’s outer coating, though usually not enough to cause any problems.
Lack of oxygen and light
Germination requires oxygen, moisture, and sometimes light. While moisture is present in the digestive tract, oxygen and light are not. This lack of essential conditions makes germination inside the body nearly impossible.
Rapid passage through the digestive tract
The digestive process moves food (including seeds) through the stomach and intestines relatively quickly, usually within 1 to 3 days. This doesn’t give seeds enough time to absorb water, swell, and begin sprouting, as they would in soil.
Excreted through stool
Seeds that are not fully digested will usually pass through the intestines and be excreted in your stool within a few days. The process is natural and generally goes unnoticed.
In very rare cases, there have been reports of seeds beginning to sprout after being excreted in faeces, especially if they pass through the digestive tract quickly and remain intact. However, this is extremely uncommon and usually occurs outside the body when the conditions are more favourable for growth.