Your trekking guide decides after assessing the situation. If the sickness is manageable, you'll continue the trek. However, if you're not in the condition to trek, for example, if you get altitude sickness, you'll return to Kathmandu. The manageable situation includes diarrhea, vomiting, and minor injuries. These issues are curable with medicines, first aid treatments, and proper rest. However, if you get severe injuries and altitude sickness, you'll need immediate medical attention. Hence, you'll get a helicopter evacuation to Pokhara or Kathmandu in such instances. Note: For emergency helicopter rescue, you must provide us with proof of travel insurance policy.