President Donald Trump at a White House press conference on Tuesday repeatedly praised a Houston doctor whose claims of proven success in treating Covid-19 with hydroxychloroquine—a medication that has become a political flashpoint—are part of a pattern of lies, misinformation, and outlandish conspiracy theories.

The president said Dr. Stella Immanuel, who in a Breitbart viral video retweeted by Trump Monday before its removal by Twitter for misinformation claimed hydroxychloroquine is a valid treatment for the coronavirus and that masks are not necessary to stop the spread of the disease, was an "important voice."

Immanuel is a member of a group called "America's Frontline Doctors," a coalition of doctors and other professionals who are spreading misinformation about the coronavirus.

According to Gizmodo:

"America's Frontline Doctors" want American medical professionals to use hydroxychloroquine to treat Covid-19 patients, something that they insist will save lives. In reality, the drug has seen only mixed success and some studies show that it can actually harm people with the disease. Remdesivir has shown more positive results as a therapeutic drug but it's not being touted by President Donald Trump in the same way for some unknown reason. Trump even told reporters in May he took the drug as a preventative measure. As the FDA has established, the drug does not cure Covid-19.

The "America's Frontline Doctors" video was removed by Twitter, as well as Facebook and YouTube, because the statements from Immanuel and others featured in it contained gross misinformation about Covid-19, which continues to infect people across the U.S. and has killed over 150,000 Americans. 

As the Daily Beast reported, Immanuel has a history of making provocative and misleading claims:

She has often claimed that gynecological problems like cysts and endometriosis are in fact caused by people having sex in their dreams with demons and witches. She alleges alien DNA is currently used in medical treatments, and that scientists are cooking up a vaccine to prevent people from being religious.

National Institutes for Health director Dr. Anthony Fauci on Tuesday pushed back on the claims from Immanuel. 

"The overwhelming prevailing clinical trials that have looked at the efficacy of hydroxychloroquine have indicated that it is not effective in coronavirus disease," said Fauci. 

But Trump at the press briefing said that "many doctors think it is extremely successful, the hydroxychloroquine," and bragged that he had taken it for 14 days and was fine. 

CNN reporter Kaitlin Collins pushed back on the president's praise for Immanuel Tuesday, noting the Houston area doctor's other outlandish statements. Trump distanced himself from those comments, said Immanuel "had tremendous success with hundreds of different patients," then quickly left the podium as Collins tried to ask a follow-up question.