Advice needed

Hi,
I'm a solo volunteer fundraiser mainly fundraising from home due to unpredictible health.
I just wondered if anyone could advise me on how I stand approaching companies asking them if they can donate things to send to charities.
I want to do a sort of gift aid pack thing to send to charities that need certain things,i.e animal rescue such as in Sri Lanka where they don't have much in veterinary supplies (bandages, wound dressings,flea treatments etc).
I wasn't sure if I approached companies asking for a donation of the above I would be breaking the law.
I would be very gratefull for any help/advice
Best wishes
Fidget