Final answer:
The Pure Food and Drug Act of 1906 required truthful labeling of food and drug products during Theodore Roosevelt's presidency. Enacted in response to 'The Jungle' by Upton Sinclair and public demand for better food and drug safety, it established inspection and sanitation standards while requiring ingredient listings.
Step-by-step explanation:
The law passed during Theodore Roosevelt's administration that required truthful labels was the Pure Food and Drug Act of 1906. This significant piece of legislation was a response to public outcry following the publication of Upton Sinclair's novel 'The Jungle,' which detailed the horrifying conditions of the meatpacking industry. The Pure Food and Drug Act enacted federal standards of inspection and sanitation for meatpackers and required drug makers to list ingredients on their products, ensuring that consumers knew what was in the food and medications they were buying.
Aside from setting sanitary standards, the act also aimed to prevent the sale of adulterated or misbranded food and drugs, a concern for health that was heightened by the era's muckraking journalism. This act, along with the Meat Inspection Act, represented Roosevelt's commitment to a 'Square Deal' for the American people, underscoring his efforts to balance the needs of consumers, laborers, and large producers.