Tomatine
Unripe tomatoes and the green parts of ripe tomatoes contain a solanine-like alkaloid (saponin) called tomatine, which may be toxic to insects, dogs, and to a lesser extent to herbivores causing diarrhoea, vomiting and intestinal irritation. Tomatine disappears as the tomato ripens (Milner et al., 2011; Straney, 1998).
Pesticide residues
Tomatoes are treated with numerous chemicals including insecticides, herbicides, etc. (Campos et al., 2007). Maximum limits for residues in food and feed are available in the Codex Alimentarius (Codex Alimentarius, 2011).