Image: 4 panels organized in a rectangle following a sequential order like a comic strip. The first panel is of a man with a very serious face stating, “Hey man, got any diphenhydramine?” The second panel is a grainy picture of the actor Tony Stark with a slightly inquisitive face and saying, “What’s that?” The third panel is an identical copy of the first image and saying, “Benadryl the allergy medicine.” The fourth and final panel is a grainy picture of Tony Stark rolling his eyes and taking a deep breath.
Tell that to the copyright lawyers
People have lost trademark rights because it’s too ubiquitous.
Aspirin was literally the brand name by Bayer but lost it.