End of constipation - one mostly passed liquid thanks to these (5,4)

'thanks to these' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'end of constipation one mostly passed liquid' is the wordplay.
'end of' indicates one should take the final letters.
'mostly' means to remove the last letter (most but not all of the word).
'liquid' indicates an anagram.
The last letter of 'constipation' is 'n'.
'one' with its last letter taken off is 'on'.
'n'+'on'+'passed'='nonpassed'
'nonpassed' anagrammed gives 'SENNA PODS'.

Can you help me to learn more?