Tally

Hi, Thanks for asking,
Create an expense account with Blood donation camp.
Debit all the expenses to this account.
it should pool all expenses directly relating to the blood donation camp. in narration mention proper detail for understanding the accounting.
Make sure(although it usually is) that the trust deed provides for carrying out camps of this nature, I.e. advancrment of general public.
If you are paying doctor fees debit it against blood donation camp expenses account.
Entry could be,
Blood donation camp exp. A/c Dr.
Bank a/c.

or

Doctor fees ac. Dr.
Cash ac
Blood donation camp exp. ac Dr.
Doctor fees ac

please put detailed narration below either of these options'entries.

Make sure the tax treatment is also identified at the time of making the entry and brief explanation is made in this regard.

under which head I should put the blood donation camp exp.

it is expenses , put under direct expenses account

Trust should be maintain all details in income & expenditure account