A row is brewing between Britain's web pharmacists. Allcures will launch its web service on Monday, offering prescription medicines delivered to the customer's door by Parcel Force and Securicor. Its only competitor, Pharmacy2u, began serving its customers at the end of last year using its own fleet of vans. It is furious that Allcures is being allowed to use a standard courier service.

Selling drugs over the net is not as simple as selling books and CDs. The Royal Pharmaceutical Society's code of ethics forbids the use of "third party carriers" for medicines in an attempt to ensure that medicines are not stolen, and that patients are always properly informed about treatment regimes and possible problems. When Pharmacy2u set up its venture in November, it also bought a courier company so that the society could not object to the service.

But Allcures' distribution methods will work out significantly cheaper, allowing it to undercut Pharmacy2u.

Daniel Lee, managing director of Pharmacy2u, believes that his competitor's arrangements will compromise standards in the pharmaceutical industry. "It's against the code of ethics - it's important that the supply chain is fulfilled by the pharmacy," he says. Lee fears that medicines could get lost among other parcels, be left on doorsteps or with neighbours, or be held in unsuitable conditions in a depot.

Alex Dickson Leach, project manager for Allcures, says its distributors will always get a signature for the medicines. The company has already secured the approval of the Royal Pharmaceutical Society. "They're very happy with what we're doing, and they've given us the go-ahead," she says. Stephen Lutener, head of pharmacy law at the society, could not confirm or deny that Allcures had the RPS approval.

Allcures is delivering NHS prescriptions for free, and hopes to make up its deficit with a £3.49 delivery charge on private prescriptions and other products, such as nappies and toiletries. Pharmacy2u is charging £5 for delivery on all products and prescriptions.

Using an internet pharmacy within the UK means filling out a health questionnaire and placing an order. However, prescriptions must still be sent through the post to the pharmacy premises before any shipment is made. Lee believes that the tight regulations will gradually be eroded by internet pharmacies attempting to cut costs and waiting times.

The US is already facing problems with internet pharmacy. Some doctors are prescribing pills online without meeting patients and assessing their condition (a man with a history of heart disease died after using Viagra bought online), and illegitimate online pharmacies are operating without licensed pharmacists. While some customers are left unaware of side effects or dangerous drug combinations, others are using the system to buy GHB, the date rape drug.

The US government is now beginning a $10m effort to crack down on the illegal sale of pharmaceuticals through the internet. The initiative includes a public education campaign about the dangers of buying prescription drugs online, and the introduction of a mark to identify legitimate and approved internet pharmacies. Lee says he would like to see a similar move in the UK.

"We are ethical and professional, but we don't know what the next people are going to be like. I'd like to see some kind of kitemark, so they meet certain criteria and are actively policed."

When Pharmacy2u was launched, there were no regulations for internet pharmacy, Lee says. "We did try and ask the society and the medicines control agency if what we were doing was legal; they didn't really have an opinion."

Within three days of the launch the Royal Pharmaceutical Society visited Lee's premises in order to inspect the operation. The society then published interim regulations in January. Lee felt exonerated by the regulations which, he says, reflected his company's standards. But he now feels that he is going to pay for taking the ethical high ground.

He has arranged an emergency meeting with the RPS to question the new stance on deliveries; if the standards are to be lowered, he will sacrifice his principles to stay in the market. "If it's being allowed then I guess we'll be going down that road," he says.