Pertussis according to the evolution of the symptoms can be divided into Kata period, spasmodic cough and recovery period, seven-month-old babies with pertussis is mainly manifested as gradually aggravated cough, cough vomiting and other symptoms, due to the extent of the disease and their own physical different, inter-individual differences in symptoms. 1. Kata period: that is, the onset of paroxysmal spasmodic cough period, which can last 1 to 2 weeks, the child more than a mild cold-like clinical symptoms, such as cough, low-grade fever, malaise, etc., with the development of the disease, the heat can gradually subside, but the cough will generally gradually worsen. 2. Spasmodic cough: can last 2 to 6 weeks or longer, mainly characterized by spasmodic cough, that is, paroxysmal, spasmodic cough, in the continuous spasmodic cough, there can be a deep and long inhalation, accompanied by high-pitched rooster-like inhalation roar, repeated, and even spit out the contents of the stomach or discharge a large amount of mucous sputum, spasmodic cough is more pronounced at night. 3. Recovery period: this period of paroxysmal spasmodic cough severity, the number of gradually weakened, coughing and vomiting after the discomfort is gradually relieved, the period lasted 2 to 3 weeks. Seven-month-old baby with the above symptoms, suspected the existence of pertussis, should seek medical attention in a timely manner, under the guidance of a doctor to identify the cause of the disease, if the diagnosis of whooping cough, it should be timely to comply with the doctor’s instructions for the appropriate treatment in order to avoid missing the opportunity for treatment.