In addition to AIDS, Fumento's writing on science have covered other such topics as global warming, ADHD, obesity, the health dangers of breast implants, teen drug use, and Agrarian utopianism. He has been highly critical of what he considers extreme alarmism over such diseases as SARS, Michael Fumento: Hysteria, Thy Name is SARS and the potential of a human avian flu pandemic. Fumento argues that many reports of threats to society are based on bad science and egregiously misused statistics (see junk science).

A common theme is his claim that many liberal environmental groups have a hysterical response to most man-made chemicals. He writes that naturally occurring food chemicals are often every bit as toxic as artificial compounds, and there is no scientific reason to view natural compounds as inherently safer. Environmental groups, he holds, will willingly accept claims that man-made compounds cause cancer, but gloss over the fact that the toxicity tests often involve quantities millions of times larger than any human being would ever ingest. Several of his articles deal with the agricultural chemical Alar, banned as a carcinogen in the United States; Fumento notes that the dosages in one Alar study were the equivalent of almost 30 thousand apples a day for life. In his view, it is impossible to test megadoses of chemicals on mice or rats and extrapolate the results to conclusions about small doses on humans. The statistical nature of these studies, often analyzed by non-statisticians, leaves them vulnerable to extrapolation error. Researchers remain divided on the utility of such tests and on the safety of Alar in particular.

He also has been a frequent critic of activist Erin Brockovich since her eponymous movie first appeared in 2000. Bestselling author and syndicated columnist Michael Fumento reports: "'Erin Brockovich,' Exposed."

Fumento describes himself as a political conservative. He has drawn criticism from liberal and veterans' activist groups for his views on Gulf War Syndrome, (His Reason Magazine article “Gulf Lore Syndrome” Michael Fumento: Gulf Lore Syndrome was a National Magazine Award Finalist in 1998 CJR - 1998 Pulitzer Prize Winners) and for his writings since 1987 Michael Fumento: AIDS - Are Heterosexuals at Risk? which stated that the threat of AIDS to the heterosexual population was greatly overstated. He promotes a position of "skepticism" towards claims that man-made chemicals cause cancer in humans.

Fumento has been outspoken in his support of adult stem cell research and critical of embryonic stem cell research, criticising what he regards as a liberal and corporate bias in favour of the latter.

Fumento also supports hydrogen fuel cell technology.

For Science Under Siege he received two awards, including the American Council on Science and Health's "Distinguished Science Journalist of 1993".

Fumento is perhaps best known for his epidemiology work, especially infectious disease outbreaks. He argues that the perception of such outbreaks becomes exaggerated or otherwise distorted by those who exploit them to serve various agendas.In November 1987 he published a landmark article, “AIDS: Are Heterosexuals at Risk?” in Commentary which in 1990 became the basis of a controversial book, The Myth of Heterosexual AIDS: How a Tragedy Has Been Distorted by the Media and Partisan Politics He has written dozens of subsequent pieces since the book. In Commentary, he challenged the presumption that, as Life magazine’s July 1985 cover declared in bold red letters, “Now No One Is Safe from AIDS.”By 1987, the theme had become common. A January U.S. News & World Report cover story declared, "The disease of them is suddenly the disease of us . . . finding fertile growth among heterosexuals." A New York Times headline that month read: “AIDS May Dwarf the Plague,” citing remarks of then-Secretary of Health and Human Services, Otis R. Bowen, that AIDS could be worse than the “Black Death”, estimated to have killed 30% to 60% of Europe's population. Surgeon General C. Everett Koop made remarks giving rise to the term “heterosexual AIDS explosion.” Oprah Winfrey told her audience, “Research studies now project that one in five — listen to me, hard to believe — one in five heterosexuals could be dead from AIDS at the end of the next three years.”

Fumento challenged that orthodoxy, for which he and even those who wrote about him were condemned and even threatened. He did so by interviewing and citing the work of epidemiologists, including the top Centers for Disease Control and Prevention (CDC) AIDS epidemiologist, Dr. Harold Jaffe, who told him, "Those who are suggesting that we are going to see an explosive spread of AIDS in the heterosexual population have to explain why this isn't happening."

Although he would be accused of claiming heterosexuals have no AIDS risk, the back cover of his AIDS book states, “The ‘myth’ of heterosexual AIDS consists of a series of myths, one of which is not that heterosexuals get AIDS. They certainly do get it . . .” Rather, he argued that while white middle-class heterosexuals were the target of AIDS propaganda, “. . . the profile of the typical victim of heterosexually transmitted AIDS is a lower-class black woman who is the regular sex partner of an IV drug user.”

As of 2007, the CDC’s “estimated numbers of cases and rates (per 100,000 population) of HIV/AIDS,” was 96.2 for black women, while only 10.8 for white ones.In a theme discussed in Commentary and greatly expounded upon in his book, Fumento described various agendas served by promoting "AIDS hysteria". These included a media catering to its primarily white, heterosexual, middle-class audience and homosexuals and their sympathizers who believed the disease needed to be “democratized” in order to spur more research funding. “On the opposite side of the spectrum Christian fundamentalists deploy it in order to underline their vision of morality,” he wrote in Commentary. He also discussed this in a 1988 New Republic cover story.

On January 13, 2006, Scripps Howard News Service announced it would terminate its business relationship with Fumento and cease carrying his column. At issue were opinion columns Fumento had written concerning the biotechnology firm Monsanto Company while working at the Hudson Institute. The connection between Fumento and Monsanto was first revealed by an investigative reporter in Business Week. General manager Peter Copeland explained that Fumento

did not tell SHNS editors, and therefore we did not tell our readers, that in 1999 Hudson received a $60,000 grant from Monsanto. [...] Our policy is that he should have disclosed that information. We apologize to our readers.

After the story was published, Fumento acknowledged that he benefited from Monsanto's grant to Hudson:

It was a $60,000 book grant to my employer, solicited back in 1999, which was applied to pre-established salary and benefits.

However, Fumento said Scripps Howard had no such policy and that the syndicate canceled his column merely upon receiving a phone call from Javers, without consulting him. Moreover, such a policy wouldn't make sense, he said, because it presumes once you’ve benefited from a grant you are considered forever in the donor's debt. That's not only hardly presumable, but clearly wasn't the case here said Fumento. In a letter published in the Rocky Mountain News Columnist Michael Fumento Defends Book Grant he said that his column didn’t begin until four years after the Monsanto grant. He wrote weekly for the news service from 2004 to 2006 he said, yet “Of my three Scripps columns mentioning Monsanto, one did so in a single sentence.” Actually, his first Scripps Howard column appears to have been in June 2003 , out of about 130 columns total. In November 1999, the same year he received the grant, Fumento wrote an article for Forbes critical of Monsanto calling the company "chicken-hearted."

Fumento has been affiliated with the following organizations:

• Independent Journalism Project - Director
• US Commission on Human Rights - AIDS analyst and attorney for the Commission
• Washington Times - legal writer - later freelancer PSEUDOSCIENCE GOING UP IN SMOKE (tqh48d00)
• Atlantic Legal Foundation - science adviser "EDITORIAL: PSEUDOSCIENCE GOING UP IN SM... (lvr08d00)
• Rocky Mountain News - editorial writer in Denver.
• American Enterprise Institute - Resident Fellow.
• Competitive Enterprise Institute - He was listed on the Institute staff in 1994 with the Warren T. Brookes Fellow in Environmental Journalism COMPETITIVE ENTERPRISE INSTITUTE (jot72e00) (clh36e00)
• Consumer Alert - 1995-96 - Science and Journalism Fellow
• Reason Magazine - science writer
• Hudson Institute - senior fellow from 1998 to 2006 Exxon Secrets A Columnist Backed by Monsanto
• National Journalism Center PR WATCH, VOL. 7, NO. 3: TOBACCO'S SECON... (vnw65c00)
• Investor's Business Daily - "National Issues" Staff writer/later freelance
• The Advancement of Sound Science Coalition (TASSC) On Advisory Board ANNUAL REPORT (any77d00)
• TrashTalk Bulletin Board - Also run by TASSC and Steve Milloy. He is a friend of Milloy PSEUDOSCIENCE GOING UP IN SMOKE (kxn35c00)
• Business Week - columnist
• Committee for a Constructive Tomorrow
• Philip Morris - He wants an "arms-length relationship with the tobacco industry" (writing articles on passive smoking) MANHATTAR INST. SEMINAR. (ozc15a00)