The most common and most likely answer to this crossword clue is the 7 letter word PANACEA
I've seen this crossword clue in The Daily Telegraph
P
A
N
A
C
E
A
More clues leading to the result PANACEA
- Effective medicine? Criticise one with added vitamin
- Aide receiving a service and fabulous treatment
- Old man swallows an excellent type of medicine?
- Criticise then serve a remedy
- Heal-all gets spread around a canapé
- Criticise expert primarily advocating non-specific cure
- Old man accepting an excellent remedy for disease
- Dash out of hospital with a remedy
- Some rampant algae can appear to be a cure-all
- Slate expert with a cure for everything
Buddy explains!

The straight part
We know that "it solves all problems" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it solves all problems = panacea.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PANACEA mean?
PANACEA noun- A remedy believed to cure all disease and prolong life that was originally sought by alchemists; a cure-all.
- Something that will solve all problems.
- The plant allheal (Valeriana officinalis), believed to cure all ills.