How to ask for medical leave?

How should I ask my boss for their permission to take leave? What is the best way?

• I am working for this firm since last 7-8 months.Everytime I go & ask for an off, my boss asks me- who will take care of my work. Other three people when they go on leaves they ask someone else to take care if required.We are just four in my team and I am the only female.When I ask them for the same, they tell me that they are busy with their own workhttp://work.My work is like providing technical help to requests received at any point of time.I cannot finish is before hand and leave. This makes me feel guilty that my work will suffer and also to do alot of thinking before approaching him.

• Answer:

  You cant have your cake and eat it too.   Set your Priorites.Either work or a day off.   Put a sick leave for a day,no one can refuse on that ground. And coming to the point of feeling guilty-Just ignore You are just being too nice,The firm existed even before your arrivaI,so stop feeling that your absence will create chaos.   It is our right to have a day off too!   But again if your job requirement is such that you are not allowed to take an off,then take an alternative as -to be available on Phone or through mail,or work from home,just to ease your Guilt.