You are allowed to be ill for up to two weeks and still be considered to be capable for work providing you continues to meet all the other basic criteria for JSA except those relating to being available for work and actively seeking work.
If you are ill for longer than two weeks then your JSA will be stopped and you will need to claim either income support or employment and support allowance.
You can only be ill twice in any one period of claiming JSA.
If you have claimed JSA for longer than one year then you can be ill twice in every year.
After your illness you will be asked to sign a written declaration which indicates the period when you were unwell.
If you are ill for a third time during a period of claiming or during any subsequent year your JSA will be stopped and you will need to claim either ESA or IS instead.
If you are ill up to eight weeks after a period in which you were entitled to:
incapacity benefit; or
severe disablement allowance; or
statutory sick pay; or
income support with a disability premium on incapacity grounds;
then your JSA will be stopped and you will need to claim your previous benefit again.