•A rapid presumption diagnosis of botulism should be made based on key symptoms-signs.•Post exercise facilitation represents a simple and reliable diagnostic test.•Antitoxin may not be necessary in patients with late-presenting mild clinical picture. Botulism is a life-threatening presynaptic disorder of the neuromuscular transmission produced by the neurotoxin elaborated by the botulinum neurotoxin-producing clostridia. We describe the management of a case series of 14 patients, members of 5 different families that were exposed to home-canned tuna and developed symptoms compatible with a mild clinical presentation of foodborne botulism. The electrophysiological study of the index case represented a reliable diagnostic test as it demonstrated a slight presynaptic dysfunction of the neuromuscular junction. Definite diagnosis was later confirmed by microbiological tests. Out of 14, only 3 patients presenting with a shorter period from symptom onset and with signs of multiple cranial neuropathies received botulinum antitoxin. All the patients remained stable and recovered progressively. Treatment with antitoxin may not be necessary in patients with late-presenting disease and mild and stable clinical picture.