If you had to medically withdraw from college, how long do you have before you have to start paying back loans?

No matter the reason you withdraw from school - Federal Student Loans provide for ONE 6 month post-attendance grace period. If you had to withdraw for medical reasons, there are deferments or forbearance applications you can complete (https://studentaid.ed.gov/sa/repay-loans/deferment... If you used up your 6 month grace period and return to school, your loans return to "in-school" status when no repayment is required. Once you finish school you would NOT receive another grace period, but would enter into repayment.

Your exit interview process should cover all this material, but keep in mind the list of deferments and forbearance clauses which apply to your loan. NONE of them are automatic and ALL must be applied for and renewed by the borrower.

i don't know

You have a grace period of six months from the day of your withdrawal. However, if you return to school, you may be eligible for a in-school deferment that will postpone your payments until you graduate or drop below half time. If you don't return to school, and you are not able to afford your payments, you can apply for a forbearance (which will postpone your payments for a limited amount of time), or you can also request and income-based repayment plan which would tie the amount of you payments to your income. This can result in a payment as low as $1 per month, if your income is very low. You can find more information about these options at www.studentloans.gov or by contacting the servicer of the loans.

6 months

Not all student loans are the same. You'd have to read your loan contract.

You have a six month grace period before you need to start paying back your student loans. If you return to school, you can defer the loans again - you can contact the loan company, fill out some paperwork, and not have to pay the loans until you leave school again/graduate.

If you don't return to school, then you have to pay the loans. If this is impossible for you, you can contact the loan company and try to work with them to lower your monthly payments, or to put your loans on hold until you can pay. But don't just not pay them - that's a very bad idea. Always try to work with the loan company.