If you’re ill with a nasty stomach bug, frequent vomiting or diarrhoea can cause you to become dehydrated.
This is because your body is losing more fluids than it’s taking in, and it’s also losing essential salts and nutrients.
Your body needs water to function properly, so when you’re losing fluids through vomiting or diarrhoea you may start to experience symptoms like feeling thirsty, tired or dizzy.