Most military interventions against other countries justified on "humanitarian" grounds actually kill more people than they save. In Kosovo NATO ranted and raved about how Yugoslavia was murdering hundreds of thousands of Kosovo Albanians, that there were mass graves all over the place, etc. Afterwards, NATO's own investigation was unable to find evidence to support those claims. It turned out there were more people killed by the NATO bombing than by the "genocide." Plus there's the fact that, as NATO admitted, atrocities against Kosovar Albanians greatly increased after the bombing started as a direct reaction to the bombing. The "humanitarian" intervention not only killed more people than the humanitarian problem, but made that problem worse. These kind of results aren't suprising because the actual motive isn't dealing with the humanitarian problem. That's just a cover story, the real reasons generally have to do with imperialism & national interests.
The only "humanitarian" intervention I can think of that saved more people than it killed was Vietnam's invasion of Cambodia. Vietnam's invasion of Cambodia started in 1978 but it didn't suceed in toppling the government (and thereby ending its atrocities) until the next year. The real reason for the invasion was a border dispute between the two countries they had been bickering over since the US was forced out. A secondary reason was the split between Moscow & Beijing - Moscow backed Vietnam but Beijing (and the US) backed Cambodia.