Does the laxative tea with senna work for constipation?

Laxative: Yes, but you need large amounts.

Senna laxative tea: Senna is a tropical/ subtropical plant (250 types) containing sennosides. The leaves & pods can be dried and used as a stimulant laxative which effects lower bowels. Senna tea can be used as a laxative.

Beware side effects: "Irritant" purgatives cause: melanosis coli (reversible pigmenting of colon lining) which is often seen with chronic senna use, cathartic colon ("floppy" colon with limited muscle tone), & soap or chemical colitis (acute inflammation within hours of "cleansing" enema). See my earlier healthtap answers regarding the longterm systemic consequences of chronic laxative use / overuse.