For a 7-month-old baby who has been suffering from diarrhoea for 20 days, it is important to be cautious with foods. Cerelac Wheat Apple is not recommended during prolonged diarrhoea, as wheat and fruits like apple may be harder to digest and could worsen the condition. Lo Lac Milk, which contains probiotics, is appropriate because it can help restore healthy gut bacteria. Most importantly, consult your paediatrician immediately, as diarrhoea lasting this long may require medical evaluation for infections, dehydration, or other underlying issues.