Brexit may affect the cost of medicines and hit UK pharmaceutical investment, a Commons committee head has warned.
Rachel Reeves, who chairs the Business, Energy and Industrial Strategy (BEIS) committee, says access to new medical products may also be at risk.
She said the uncertainty around Brexit was "very concerning", as MPs prepare to examine its effects on the industry.
They include the sector's access to highly skilled workers after the UK leaves the Euopean Union.
Ms Reeves said the evidence MPs had received suggested Brexit could threaten "the cost of medicines, investment in the UK and access to new and innovative research and products".
"There are serious concerns raised around the future regulation of pharmaceuticals, mutual recognition of medicines, and the prospect of damaging disruption to cross-EU drug supply chains," she said.
"This is very concerning, with uncertainty risking the UK becoming a less desirable place for investment and development in a growing, productive industry.
"We are keen to examine the detail of these concerns and to hear from the industry what it wants from the government to ensure the smoothest possible transition as we leave the EU."
Brexit will mean the relocation of the European Medicines Agency from London to Amsterdam.
The MPs' inquiry comes despite the announcement last week of two big deals in the UK's pharma sector.
The government said then that the decisions by MSD, known as Merck in North America, and Germany's Qiagen illustrated confidence in its recently announced industrial strategy for when the UK leaves the EU.
The industrial strategy white paper outlines the government's plans to support more research and development, encourage firms to embrace new technology and boost the economy.
A report in the Sunday Times said more major investment for the sector is due to be announced soon, with GlaxoSmithKline expected to reveal a new research partnership.
The Business committee has been seeking views from across the sector and has received written submissions from big pharmaceutical companies, trade unions, industry bodies and the government.
The submissions have been published ahead of a public evidence session on Tuesday when the committee will question witnesses from the industry on the impact of Brexit.
It will consider different outcomes relating to future cross-border customs and trading arrangements, and consider what the government should aim to achieve in negotiations.
Those appearing before the committee will include the Association of the British Pharmaceutical Industry (APBI) and Belgian-headquartered Janssen Pharmaceutical, part of US giant Johnson & Johnson.
The ABPI said the inquiry was important.
"The written evidence received by the committee highlights how regulatory cooperation, a frictionless system for trade and access to research funding, collaboration and talent, underpin the successful development and delivery of medicines," a spokesperson said.
"Evidence also shows that 45 million packs of medicines go from Britain to the EU every month and 37 million come the other way. With this whole system at stake, clarity on medicines regulation and trade is urgently required for all patients across Europe."