This is a remedy whose use in acute homeopathy is primarily for abdominal disorders.
It is renowned for use in the colic of babies – consider the symptoms of being worse from drinking milk with smelly sour stools and you have Mag Mur. If the sufferer also has greenish stools this is a valuable confirmation of this remedy (although you should compare Chamomilla and Ipecac)
It is also important to compare Mag mur with Rheum and Nat phos both of which also have sourness as a key feature. Nat phos sufferers usually have strong acidity with their troubles whereas Rheum is used primariily for diarrhoea accompanying teething troubles.
Stools green
All discharges sour
Better from fresh air
Worse from drinking milk
Colic
Constipation
Diarrhoea
Insomnia
Teething