Poulter was elected as the Member of Parliament for Central Suffolk and North Ipswich at the 2010 general election, receiving 27,125 votes, increasing the Conservative majority of his predecessor, Michael Lord, seeing a vote share of 50.8%. In 2011, he was credited with a "lifesaving" intervention in Parliament when he persuaded fellow Conservative MP Guy Opperman to seek urgent medical treatment. Opperman subsequently had a brain tumour removed. Poulter announced he would resign from the British Medical Association in 2012, following an announced doctors' strike. He said he did not believe "striking as a doctor could ever be justified" and defended plans for doctors' pensions. In September 2012, Poulter became the Parliamentary Under Secretary of State at the Department of Health. His primary responsibilities as a Health Minister were for workforce issues, NHS estates and IT systems. After the 2015 general election, Poulter returned to the back benches, and to working part-time as a doctor. In October 2015, Poulter expressed his support for protests by doctors and others against the Conservative government's proposed changes to the junior doctors' contract. In April 2016, Poulter widened his criticism of the Conservative government, in a Guardian article. In January 2016, he announced his support for medicinal cannabis saying it should "be used and encouraged". Poulter was opposed to Brexit prior to the 2016 EU membership referendum. Despite opposing Brexit prior to 2016, Poulter consistently voted along party lines concerning leaving the EU, including votes to allow no deal and to suppress yellowhammer. He also repeatedly expressed support for the suspension of parliament by Boris Johnson in 2019, which was subsequently found to be unlawful. The 2019 People-Power Index which ranks MPs ranked Poulter at 627 in the list of 650.
''Sunday Times'' libel case
In November 2017, the Sunday Times printed accusations made to the newspaper by Andrew Bridgen MP that Poulter had sexually assaulted three female MPs eight years previously. The Conservative Party Panel investigated the matter and exonerated Poulter, confirming that no woman had ever made a complaint about him. It dismissed the Bridgen claims as having "no reliable evidence" to support them. In February 2019, the Sunday Times apologised in open court to Poulter, acknowledging that the allegations were false, defamatory and should not have been published. The articles were removed from the newspaper's website and Times Newspapers Limited agreed that it would not republish the same or similar allegations about Poulter in the future. The Sunday Times paid substantial damages to him, as well as his legal costs.