You can take it every day, if you have chronic Cold or allergy issues but a minimum quantity of 10-15ml once in the early morning on an empty stomach will be much more effective.
Next Steps
Ayurveda has the best treatment for Chronic Bronchitis & Allergies.
Consult on Practo.
Health Tips
Don't take it in Summer season or Sunny days.
Drink warm water.
Avoid Allergens like Dust, pollen etc.