In the twenty-first century, allergies to food products – particularly peanuts – are high-profile health concerns. Most food products carry warnings on their packages indicating potential peanut hazards, which at worst could cause a fatal anaphylactic shock. However, allergy has not always occupied such a prominent space in the public imagination. Indeed, the term ‘allergy’ was itself only coined at the start of the twentieth century, even though, presumably, certain consumers have always been allergic to particular foods. Then again, it is plausible that the dramatic twentieth-century shift towards consuming highly processed, manufactured food has left in its wake a host of new, modern, dietary-related problems including allergy. In Another Person's Poison: A History of Food Allergy, Matthew Smith does not set out to establish decisively whether we are more allergic to certain foods today than in the past. Instead, he provides an insightful account of the contentious debates that have surrounded food allergy over the last century, the various historical actors who expressed concern about allergy, and their motivations. Ultimately, food allergy emerges from Smith's study as an ambiguous, perplexing and deeply contested medical condition. Indeed, one of Smith's main aims is to encourage doctors, researchers and the public to recognize food allergy as complex and multifaceted as opposed to contextualizing the problem through the tunnel vision of laboratory experimentation or defining it as a neat, precise concept.

Assessing the history of a disease before scientists ‘invented’ it is never an easy task. In his opening chapter, Smith skilfully weaves through the potential hazards of retrospective diagnosis to trace the prehistory of modern food allergy. Rather than focusing entirely on scientific aspects of food, he incorporates the perspectives of nineteenth-century patients, including individuals who were plagued by eggs. Even when these people refrained from enjoying an egg with their breakfast, they found that eggs were everywhere – in cakes, puddings and even coffees. While it is difficult, if not impossible, to ascertain whether such allergies were as common in the nineteenth century as appears to be the case today, Smith makes clear that certain people have always had idiosyncratic responses to particular food items. Indeed, hidden ingredients in seemingly harmless food products have always caused years of personal misery.

Even when early twentieth-century doctors and scientists began to appreciate the specific nature of food allergy, questions arose about how to define and manage the problem. Was food allergy best understood through laboratory experimentation or by painstakingly observing the daily routines of patients? Was the problem physiological or psychosomatic? And how should the ecological or environmental aspects of food allergy be addressed? In many ways, as Smith ably demonstrates, food allergy became a territory in which various competing strands of medicine battled for authority. Food allergy became clinically significant at a time of rapid medical professionalization and specialism, but also one of intense rivalism within medicine. In his second chapter, Smith outlines tensions between early twentieth-century physicians who either stressed the importance of individualism when treating patients or adopted reductionist approaches, in this instance rooted in immunology.

As Smith's subsequent chapters demonstrate, numerous high-profile and well-regarded medical scientists began to associate food allergy with an array of medical complaints. Allergy established itself as a serious specialism within medicine, even if it initially failed to secure significantly high levels of prestige or importance. From the 1950s, an environmental turn took place in food allergy as food additives and processed foods were highlighted as potentially disruptive allergens. However, as Smith details, environmental perspectives clashed with psychosomatic ones. Post-war perspectives on food allergy reflected competing ideologies, causing a split within the allergy community, or, in the words of one allergist, a ‘panic in the pantry’ (p. 99). In the final chapter of Another Person's Poison, Smith explores the relatively recent fixation with peanut allergy. As Smith argues, the panic over peanuts and anaphylactic shocks has helped to transform food allergy from a somewhat niche topic into a major public-health issue. Instead of continuing to debate the value of competing ideologies or particular types of treatment, allergists now pay more attention to the concerns of parents and patients who seek to raise awareness of peanut contamination and lobby for better food packaging labels.

In Another Person's Poison, Matthew Smith provides a thoughtfully considered and well-written account of the rise of food allergy in the public and medical imagination. Food allergy emerges from Smith's study as a complex, nuanced medical condition with ramifications that intertwine with theoretical, clinical, professional and commercial interests. The book will prove of interest to both academic and public audiences with an interest in the history of food and medicine.