Marijuana remains a deeply debated topic across the world, with discussions ranging from its suspected medicinal properties to its potential health concerns. While legislation continues to lean towards legalisation for recreational and medicinal use, there’s an undeniable need for thorough, science-driven research to guide public opinion. This is exactly what Peggy Mann’s updated and expanded edition of “Pot Safari” offers—a detailed exploration of marijuana’s impact on health, based on insights from renowned researchers.

Originally published in 1982 and reissued for contemporary audiences in 2025, “Pot Safari: A Visit to the Top Marijuana Researchers in the U.S.” examines marijuana’s effects on various systems within the human body, from the brain to reproduction and even the immune system. This original, and arguably seminal, research work was groundbreaking, with much of its revelations being ahead of its time. In fact such recent research books such as Cannabis in Medicine: An Evidence-Based Approach by Dr Ken Finn and the very latest compendium on cannabis harms by Professors Reece and Hulse Epidemiology of Cannabis – 1st Edition, acknowledge the Pot Safari for its significance. 

As the research since the launch of original work was first published has grown exponentially, the complexities and concerns about this now heavily engineered ‘plant’ have grown with it.  Science not only confirms initial concerns about the multiple toxicities of this substance, but has revealed its quite disturbing and far reaching harms.

Even though the long touted ‘panacea potential’ of pot has now been totally debunked, real science along with responsible and highly regulated pharmaceutical companies, continue to research what potential positive use this plant may have in the field of medicine. Sadly, the ‘cowboys’ of the ‘vote for medicine’ culture are now utterly ruining any further therapeutic potential of this plant, with their continued reckless claims and ‘snake-oil’ sales tactics – the harms of which will have an intergenerational echo.

Pot Safari, with its perspectives from leading scientists and a price of only £11.99, sees this work as a must-read for those seeking an informed viewpoint on marijuana’s biological influence.

What Is Pot Safari About?

“Pot Safari” is not just another opinionated commentary on marijuana. It is a factual and science-rich narrative that comes from the unique experience of Peggy Mann, a journalist who dedicated much of her career to exposing the hazards of substance abuse. She spent four months visiting laboratories and engaging directly with the top marijuana researchers in the United States. Through her “safari,” Mann gathered first-hand accounts and data, much of which had not been presented to the general public before.

The book meticulously explores marijuana’s effects in various areas, including:

• The brain and cognitive function
• Reproductive health and pregnancy
• The lungs, heart, and respiratory system
• The immune system and overall health responses

By presenting factual, in-depth scientific information and first-hand accounts, Mann raises an important counterpoint to the prevailing notion that marijuana is inherently safe.

Peggy Mann’s Safari into Marijuana Research

To craft “Pot Safari,” Peggy Mann travelled extensively across the United States, visiting leading researchers in their own laboratories. One standout collaboration was with Dr. Robert Heath, a pioneer in psychiatry and neurology. Dr. Heath revealed alarming findings regarding marijuana’s effects on the brain, particularly the accumulation of its active compound, THC, in fatty tissues like the brain and reproductive organs.

Mann’s visit to the Marine Biology Laboratory in Massachusetts stands out as another significant part of her research. Here, Dr Isidoriades conducted groundbreaking studies on long-term male cannabis users. He investigated the potential effects on sperm under an electron microscope. These in-depth studies provide a clearer understanding of cannabis’ impact on reproduction. This is an area often overlooked in public narratives surrounding marijuana use.

Breaking Down Marijuana’s Health Effects

One of the greatest strengths of “Pot Safari” is its clear and structured approach. Each chapter shines a light on marijuana’s effects on a specific body system, making it easier for readers to grasp complex findings. Here’s an overview of the key health hazards explored in the book:

1. Marijuana and the Brain

Mann details the work of researchers who studied the effects of marijuana on brain cells—both in monkeys and humans. The findings reveal significant changes in brain structure and function, particularly in young users. These include impaired driving ability, reduced endorphin production (pleasure centre cells), and “pot personality” symptoms. The insights from these groundbreaking studies suggest that casual marijuana use can provoke long-term neurological consequences.

2. Reproductive Health

Research from Dr. Ethel Sassenrath and others highlights the dangers of cannabis use during pregnancy. Their studies found short and long-term effects on infants exposed to THC, including developmental abnormalities. The book also dives into the male side of reproductive issues, showing abnormal sperm patterns and reduced testosterone levels in regular marijuana users.

3. The Lungs and Respiratory System

Mann explores how marijuana affects the lungs, often in ways more harmful than tobacco. Case studies of long-term users revealed pre-cancerous lesions, higher airway resistance, and emphysema-like conditions in young adults. Dr. Tashkin’s discoveries about hidden lung symptoms in marijuana users make this section particularly compelling.

4. Effects on the Cardiovascular System and Heart

Dr. Wilbert Aronow’s research sheds light on marijuana’s impact on heart rate and blood pressure. Users with pre-existing heart conditions are shown to experience worsened symptoms compared to those who smoke tobacco.

5. Harm to the Immune System

Chapters on the immune system examine how T-lymphocyte suppression, prolonged use, and impaired antibody responses put frequent users at higher risk for secondary infections and illnesses.

Relevance of “Pot Safari” in 2025

With marijuana now decriminalised or fully legalised in many parts of the western world, the need for balanced, evidence-based information is greater than ever. Most often, public opinion around cannabis remains shaped by its medicinal use or claims of safety. Peggy Mann’s “Pot Safari” serves as a critical resource to provide another perspective—showing the science behind marijuana’s potential harms.

Additionally, this updated reissue includes commentary from esteemed professionals like Dr. Kenneth Finn, Editor of Cannabis in Medicine, and Dr. Robert DuPont, Founder of the National Institute on Drug Abuse (NIDA). These additions underline the ongoing importance of this research in shaping conversations around cannabis.

Why You Should Read Pot Safari

Whether you’re an educator, medical professional, government policymaker, or concerned parent, “Pot Safari” provides invaluable insights into the often-overlooked biological consequences of marijuana. It’s also a resource for teenagers, especially those navigating peer pressure to try cannabis recreationally. At a modest price of £11.99, this book delivers key resources and knowledge, empowering readers to make informed decisions.

“Pot Safari” is not simply a book—it is an educational tool and a beacon of scientific truth in an ocean of misinformation. Peggy Mann’s work, updated with modern commentary, bridges the gap between cannabis research and public awareness. Comprehensive yet engaging, this reissue underscores the importance of understanding the risks involved with marijuana use—whether you’re a parent, policymaker, or simply curious about the topic.

Want to uncover the untold story behind marijuana research?