First, you never take anything that increases immunity constantly unless you've been told to do so by a health professional for medical reasons. Otherwise you overstimulate your immune system. Some immune stimulating herbs, such as echinacea, should never be taken regularly, only when needed. Some are more balancing, such as Moducare, and can be taken regularly. It just depends on whether it's for support or for a current condition. Second, calendula isn't an immune system herb nor is it great for fighting infection, and if you don't have an infection, you don't want to fight one, as again, you just waste the herb, making it less likely to work when you need it, and have the overstimulation problem. Calendula is usually used topically for rashes and itching; the tincture isn't used as regularly, but you won't find it in immune support formulas as you would, say, astragulas. I see no benefit in taking this herb regularly unless there's something specific going on you haven't mentioned.
i use it as a ticture.to increase immunity and fight infection.
What are you using it for? If it's used as a tea not a problem for most people.
It's possible you could have an allergic reaction.