A Surrey NHS Trust has been criticised after it emerged a cancer drug it sold abroad is now in short-supply.
Parliamentary candidates for Guildford said the Royal Surrey Hospital Trust was wrong to export drugs for profit.
One of the cancer drugs the trust was selling has now been placed on a list of medicines that are deemed hard to get hold of in England.
The trust said there was "absolutely no evidence" to suggest its practices had contributed to the shortage.
Conservative Anne Milton has written to the trust's chief executive seeking reassurances the practice will not happen again.
She said: "The Royal Surrey's job is to treat patients and not to make money, it is not acceptable for the NHS or the Royal Surrey to put profit before patient care."
"The Royal Surrey does an excellent job looking after local people and it needs to continue to do what it does well and stop this sort of activity that can be so damaging."
Liberal Democrat Sue Doughty said she would also be seeking reassurances the sales had not led to a shortage of cancer drugs.
She said: "It's not what they should be doing. They should be meeting budgets through efficiencies not through drugs sales."
Labour's Tim Shand said: "'I don't think an NHS hospital should be selling drugs abroad.
"It should be concentrating on looking after patients rather than fringe activities such as this."
The trust was criticised by the Department of Health in February when it confirmed it had made a £300,000 profit from the trade during the previous year.
The list of drugs being sold was revealed on Wednesday in the Health Service Journal (HSJ) after a freedom of information request.
The HSJ said the trust sold 240 packs of the cancer drug imatinib between May and October 2009. Less than a month later, in November 2009, the drug was listed as being in short supply.
A spokeswoman for the trust said it was "misleading" to suggest it had sold drugs on the short-supply list.
The last order for imatinib - also known as Glivec - was sent out on 14 October and the drug was listed as being in short supply on 6 November, she said.
She said: "In the two months prior to that only small quantities were sold. There is also absolutely no evidence to suggest that the trust has played a part in creating a shortage of drugs."
The candidates announced for Guildford are: Lib Dem: Sue Doughty; UK Independence Party: Mazhar Manzoor; Conservative: Anne Milton; The Peace Party: John Morris; Labour: Tim Shand.