How to add product lot nr, product expiry

hi,
I don’t find any field to add expiry date, lot (batch no.), …
I did it wel using attributes, but the problem is that I don’t get a way to do search products from which they are near to expiry,

other problem is for batch nr. we are selling medications, so every purchase come the same product name, but with different batch number, it means that we should trace the product from buyig to sell it, so when we sell product A, if fact we sell product A, batch; 1234 , and may be in the other order, product A, batch 6789,

please nay help?

Hello
The good way is to use Equipement Module who manage unique Serial number (and version number of a group of product).
In you case, you can define a expiry date with extrafields on Equipment.
More informations Here (in French sorry) : http://www.benke.fr/index.php?option=com_content&view=article&id=47:module-equipement-&catid=18:dolibarr&Itemid=25
An english tutorial version will come soon